The sign at the entrance warns me that this is an espace de silence, a place of silence. I’m thinking we should be tiptoeing rather than noisily lugging our suitcases from the car but we’re staying the night.

I’d emailed to make a reservation the moment I knew we’d be in the area but I didn’t hear anything back until, a month or so later, I received a message via Facebook. It was from Florence, who looks after the bookings at the priory, and she wrote that her emails to me kept bouncing back. I was dead impressed that she’d used social media to track me down and so I’m delighted to meet her now in the small office at the main entrance. She’s witty and warm, and tells us that although silence might be an overstatement, keeping our voices down will certainly be appreciated. We’re given the code to the main door and told which will be our bedrooms. Although, of course, they’re cells. The two upper floors are lined with nearly a hundred of them, with the resident Dominican friars living in the part that overlooks the valley. We’re the only guests apart from a group of Japanese architecture students and we’re free to come and go as we please, and to walk wherever we want, except for those areas expressly marked private.

And so begins a memorable visit to one of the twentieth century’s greatest buildings.

We’ve arrived in the bright sunshine of the afternoon, having driven south from Burgundy through a beautifully hilly landscape. I had slammed on the brakes the moment I saw La Tourette on the opposite slope of the valley. I’ve studied photos of this building for nearly forty years so it was a heart-stopping moment to come face-to-face with the real thing.

So that’s how you sit in the landscape.

I’d always been a little anxious about visiting La Tourette, knowing that it’s one of Le Corbusier’s most celebrated works. What if I didn’t like it? This is not your conventional religious building, after all. It opened in 1959, and is famous for its austerity and its use of reinforced concrete. Le Corbusier was drawn to the commission by Father Marie-Alain Couturier, the hugely influential figure who was instrumental in bringing a new artistic expression to the Catholic church in France after the Second World War. Name any great religious work in France of this period, such as Matisse’s designs for the Rosary chapel at  Vence, Fernand Léger’s mosaics in Audincourt and Plateau d’Assy, and Le Corbusier’s masterful chapel at Ronchamp, and the hand of Father Couturier is involved. One of the first meetings he had with Le Corbusier was when he turned up at his home in Paris. Yvonne was unnerved to find on her doorstep a priest dressed in white robes. It didn’t stop her playing one of her practical jokes, slipping a whoopee cushion on the chair as he was about to sit down. According to Le Corbusier, the meeting went extremely well after this rather unusual way of breaking the ice. Sadly, Couturier was dead by the time La Tourette was completed. (The incident figures in my novel, Loving Le Corbusier.)

In French, the place is called a couvent, or convent, but priory is a better translation as most people today think of convents being filled with nuns, and this was a building for men. Monasteries tend to be secluded places for prayer and retreat but this new priory sought an active role in the community. The original Dominican friars were from a remote area in the Alps and felt that having a priory close to the city of Lyon and its university would make it more visible. When it opened it was the study centre for all Dominicans in the region, which is why it was designed on this scale. Today, though, only fifteen friars live there, most of them working in the community, and visitors tend to be more interested in the architecture than religion.

I’ve always found La Tourette difficult to work out but now I’m here I can’t for the life of me think why. It is amazingly simple. The large block of the church is built into the land, closing the U-shape of the main building, which is held aloft on a series of slender piloti, rising above the steep slope of the land. There’s a courtyard but only part of it has been terraced and made into a rough kind of a cloister, where simple grass grows rather than anything prettier.

Rough is the word for this building. This is Brutalist architecture, and as you arrive, you can’t fail to notice the rawness of the concrete, stained and cracked and as coarse as the name Brutalism implies. Unkempt grass covers various roofs, some of which have protruding ‘light cannons’ which draw natural light into the spaces below (these were the work of Le Corbusier’s friend Iannis Xenakis, the man more famously involved in the tented Philips pavilion that Le Corbusier designed for  Expo ’58 in Brussels). Inside, you find crumbling concrete lintels and wonky frames holding in the walls of the glass, and while I’m sure they have degraded over time, I can’t help feeling that they were rough at the beginning. This roughness is on purpose. Le Corbusier wasn’t interested in ultra-fine finishes and embraced the flaws in materials like concrete. It’s a wabi sabi quality, the idea that beauty can lie in imperfection.

So much is familiar from having visited Le Corbusier’s other buildings. A concrete water spout drawing water from the roof is straight out of Ronchamp. There is a strong use of colour, just as you find in his Unité d’habitations, with a wavy blob of black-paint on some of the doors to mark the handle. The cells themselves are like the children’s rooms in the Unité’s, with space enough for a surprisingly comfortable bed, a wooden desk and a pleasant little balcony with concrete latticework, just like the balconies in Marseille. There’s a washbasin and a storage unit that also acts as bedhead.

The bathroom is along the corridor, with bath, showers and toilets behind separate doors and water pipes painted a vibrant blue, which reminds me of the colour-coded pipes used by Piano and Rodgers at the Pompidou Centre in Paris. Sections of tinted glass, known as Mondrian panels because of their primary colours, enliven the windows overlooking the cloister and remind me of the panel of coloured glass set into the window in Le Corbusier’s own apartment in Paris.

The most arresting feature throughout the building is the ventilation. Everywhere, set within windows, within walls, and next to doors, are slender openings with hinged wooden doors painted in bright primary colours. There are metal tubes that swivel open, too. It means that airflow can pass through the building easily without any loss of security. The external ones are meshed to keep out insects. When they’re closed you barely notice them. At night, I leave my ventilation door open to the corridor outside and also the one next to the balcony door and a wonderful breeze floats through my room during the night. (He used the same thing in the Cultural Centre at nearby Firminy.) It’s brilliant and I can’t help wondering why it hasn’t been used more, especially in countries like Australia where cross ventilation is such a blessing on a hot day. Nothing mechanical, just the constant drawing of air through one space to another. Talk about simple.

We explore the place. There is something at every turn, like the way the windows at the end of each corridor are blocked by angled slabs of concrete (or concrete flowers, as they’re called) so that your mind isn’t distracted by the view outside. And yet there is a huge wall of undulating glass in the refectory that encourages you to gaze out to the valley beyond. It’s all a question of balance.

I’m eager to see the church. It’s oddly reached, along a slope whose downward angle exactly matches the upward slope of the roof of the circulation space you’ve just left. It makes me think of the ramps in Villa Savoye and the Maison La Roche. At the end there’s a curved doorway with a massively thick metal door like one in a submarine, as though built to withstand a flood. You have to step through the entrance, rather as you do in an Asian temple.

The church is the space I had feared I might not like but it’s extraordinary. The altar occupies a central place with seating for the friars at the lowest end, and an open space for the public at the other.  A sliver of window tops the western wall, allowing a line of light just as you find in Ronchamp. There are low windows, too, letting in light to the choir that is coloured by their painted reveals, giving the impression of stained glass without the bother of the glass itself. It’s a huge concrete box and yet it feels majestic rather than overbearing. There’s little to distract you and that contributes to its overwhelming sense of peacefulness. Comparing it to the busy exuberance of a Baroque interior, I know which one makes me feel more focussed.

As guests of the priory, even though Florence tells us there’s no expectation that we take part in the spiritual life there, we attend Vespers. It’s a lovely experience. The friars are dressed in white robes. One friar has obviously had a tiring day and can’t stop yawning. The altar is set with candles and the fading light outside means the space feels as cavernous as a cathedral. The reverberation of the singing is magnificent.

Afterwards we eat in the refectory next door, where one of the friars greets us warmly. I’m expecting that we might have to say grace but there’s nothing like that. It’s a large space with the longest wall filled with glass panels of unequal width, looking out to twinkling village lights in the distance. The friars dine in their own space and so it’s just Anthony and me and the Japanese students at separate tables. The food is basic – slices of watermelon then stuffed tomatoes followed by a sickly chocolate mousse out of a packet – but I would happily eat bread and water in this space. I’m grateful, though, for the bottle of red wine (the local Beaujolais, of course) that comes with it. A laminated sign with Modulor man shows us how not to cut the bread. Breakfast the next morning is similarly basic but equally welcome. I check out the kitchen next to it, with its cheerfully painted storage units, their simple wooden door handles like those he used in his own homes.

I sleep amazingly well in my cell despite the relentless hooting of an owl outside and wake as daylight begins to colour the sky beyond the trees. And so I slip out, ambling through the woodland that surrounds La Tourette and lingering at the beautiful graveyard where the friars of the past are buried, the graves marked by simple wooden crosses. There are classical relics and old buildings such as a quaint ice-house dotted through the parkland, clues to the more secular life of the old Chateau of La Tourette in whose grounds the priory sits. I noticed the previous evening a number of people walking their dogs or sitting chatting on benches, and I liked how the parkland is shared. As I return for breakfast, stopping every few steps to marvel at a new angle and different view of the building, I notice I am being watched by a friar as he sips his morning cup of coffee on his balcony. I think how lucky he is to live there.

With breakfast out of the way, we’re able to see La Tourette’s pièce de résistance, the crypt. It’s not underneath the main church but to one side, at a lower level, so that you can look into it from the church. Being within it, though, is a totally different experience. Access is usually denied but Florence told us we could enter as the architecture students would be there, too. It’s approached via a precarious set of narrow steps from the Sacristy on one side of the church which leads you into a pitch-black corridor that runs underneath the nave and then out into the frankly astonishing space of the crypt.

It was here that the friars performed an individual mass each day but that was abolished after Vatican II. There are six separate altars, stepping down as the floor follows the natural contours of the land. Extraordinary circular skylights give a diffused, coloured light. Every surface is painted, although the rough concrete is never masked. It is an sublime space – tilting, stepped, colourful, moodily lit. I could’ve stayed for hours but the Japanese students are planning to film there and want us out. “You cannot be here,” says their tutor in stilted English and I want to say, “Yes, I know, I can’t believe it either” but instead I assure him we’ll be gone in a moment.

We spend much of the morning walking around, exploring spaces we hadn’t noticed the previous day. I feel so privileged to have the run of the place, to be able to open doors and find a small chapel or a common room or a library. And I think what a perfect place it would be to stay and work on a book (there, I’ve set it in motion by even mentioning it). I’m reluctant to leave.

Le Corbusier died in 1965 while swimming close to his holiday home at Roquebrune-Cap-Martin. His body was placed here overnight on its journey back to Paris. It’s sentimental, I know, but just being in this special place, knowing that he was here and that his body was here, means a lot to me. Architecture is always emotional. My fear was that I would find this building hard to love, that its roughness and austerity would not move me. But of course it’s astonishing. It’s emotional, it’s thoughtful, it’s calm, it’s uplifting, and it’s Le Corbusier down to the very last grain of sand in its concrete.

I’m obviously a very slow leaner.