Meet Jean-Nicolas

He led Inowai. He ran real estate at Unibra. Today, Jean-Nicolas starts from scratch.

At 48 rue de Diekirch in Arlon, a five-minute walk from the town center, an old building has just finished its transformation. What used to be a restaurant on the ground floor and five modest apartments above is now three distinct homes. A studio with high ceilings under the roof. A two-bedroom apartment with a loggia. A three-bedroom duplex with a private garden and two bathrooms.

Jean-Nicolas Montrieux is the owner. He bought the building with his wife in 2008 as a rental investment. Eighteen years later, he is finishing the renovation and putting it on the market. In between, he spent thirteen years at INOWAI, where he became Managing Director and Partner. He then ran the real estate arm of Belgian industrial family group Unibra for two years. In April 2026, he launched his own company: Realiven. Somewhere between developer and property trader.

The general contractor on the project is Alexandre Dron from Eco-renov. The brief was simple. Mix typologies. Avoid the small low-quality units you see everywhere in Arlon city center. Bring families back to the center.

What makes this project interesting is the story behind it. It was almost a coliving. The first version of the project, post-Covid, was a shared-living concept. The municipality said no. So Jean-Nicolas and his wife went back to the drawing board and chose a more traditional path. Three apartments. Three lives. One building.

The result is rare in Arlon. A three-bedroom duplex with a garden in a city center. A studio with real ceiling height under the roof. Raw concrete ceilings left exposed because the construction team noticed the formwork left a beautiful finish. Wood cladding that nods to the old shop front. A wooden staircase that was meant to stay original but was rebuilt entirely for quality and acoustics.

In this visit with She Said Yes!, Jean-Nicolas opens the doors to his first project as an independent developer. From the future garden to the rooftop studio, every choice tells the story of a building that took eighteen years to find its final shape.

City

Arlon

Date

May 2026

Photos & Video

She Said Yes!

SSY      Hi Jean-Nicolas. We are in Arlon, on a project you have owned for eighteen years. Can you tell us how it started?

JNM      We bought this building in 2008 with my wife. It was purely a rental investment at the time. We bought it in two steps. First the upper floors with five small apartments. Not high-end, but it generated yield and helped us pay down the loan. Later we bought the ground floor, which used to be a restaurant before being converted into a flat.

 

SSY      Why the renovation now, after all these years?

JNM     Once we owned the whole building, we realized it was getting old. Structural work was needed. We could not just keep changing kitchens and bathrooms one by one. We had to go deeper. So we hired an architect and the project started from there.

 

SSY      The first idea was a coliving. What happened?

JNM     Yes, we wanted to do a coliving here a few years ago. It was post-Covid. We had a Teams meeting with the municipality. Honestly, it did not go well. They were not ready for that kind of project. So we sat down again with the architect, looked at our objectives with my wife, and decided to go back to a more traditional rental building.

 

SSY      Why three different apartment types in such a small building?

JNM     In Arlon city center, you find a lot of small low-quality apartments. Not all of them, but many. We wanted to stand out. So we decided to do three categories. A studio under the roof. A two-bedroom apartment. And a three-bedroom duplex for families, with a garden, two bathrooms, and a parental suite. That last one does not really exist in this market. I am curious to see how it performs.

 

SSY      Why is it important to bring families to the center?

JNM     Because mixity makes a city. If you only build small units, you only attract one type of resident. Cities need families too. That is how neighborhoods stay alive.

 

SSY      The entrance hall is special. You kept a reference to the old shop front?

JNM     Exactly. There used to be a shop window on the street. We had to wall it up because the street is now residential. But to keep a memory of the building’s past, the old window will be marked with a wood cladding on the facade. It is a small detail but it matters.

 

SSY      The ground floor and first floor are a duplex with a garden. That is rare in a city center. How did you make it work?

JNM    The original building had a huge extension that went deep into the back. It was the old commercial space. We decided to demolish it and rebuild a smaller annex. That gave us back a real garden in full ground. Today, urbanism rules don’t allow you to fill the interior of a block anymore. So bringing back the soil was the responsible thing to do.

 

SSY      The concrete ceiling in the living area is exposed. Was that planned?

JNM     No, it was a happy accident. When we changed the slabs, we removed the formwork and saw that the raw concrete looked beautiful. We talked with the contractor and decided to keep it. It brings something different. Then we picked a light wood that works with it. Concrete and light wood is a neutral base. People can decorate however they want.

 

SSY      The staircase is new but looks traditional. Why?

JNM     The original idea was to keep the old wooden staircase. But once we saw the quality level of the rest of the renovation, we decided to redo it completely. It also helps with acoustics and safety. Sometimes you have to commit fully.

 

SSY      You kept the front facade but rebuilt almost everything else. Why?

JNM     The municipality wanted us to keep the facade. We agreed because it gives the building its identity. But during the renovation we discovered that some elements were either not optimal or too fragile. So we rebuilt more than we initially planned. In the end, what remains is mostly the front facade and part of the back walls. Everything else is new.

 

SSY      The building is ready for the future. What is already prepared?

JNM      Every apartment has its own heat pump. We left technical ducts ready for solar panels on the roof and EV charging stations on the parking spots. We did not install them ourselves because we are selling. We leave that freedom to the future owners. But everything is prepared.

 

SSY      The duplex has a clear separation between parents and kids. Was that intentional?

JNM     Yes. The living spaces are on the ground floor. The bedrooms are upstairs, organized in two zones. On one side, the two kids’ bedrooms with their own bathroom. On the other side, the parental suite with a bedroom, a dressing area and a private bathroom. It is a real family layout.

 

SSY      The two-bedroom on the second floor has a loggia. Why was that important?

JNM     Because in a city center you rarely get a garden. So we wanted a real outdoor space that you can use all year. A loggia is covered, protected from the wind, calm. You can enjoy it in spring, summer, autumn. It is not just a balcony, it is a real extension of the living room.

 

SSY      The studio on the top floor is around 40 square meters. How did you make it feel bigger?

JNM     We left it completely open. I thought about putting a partition for the bedroom area but decided against it. The ceiling height is what makes it work. You don’t feel like you are in a studio. You feel like you are in a real apartment. We also changed the whole roof, which made the insulation much better.

 

SSY      Who built it?

JNM     The general contractor is Alexandre Dron from Eco-renov. We had worked with him before. He took the whole site in hand as general contractor and followed every trade from start to finish. His mission is almost over now.

 

SSY      When is delivery?

JNM     June 2026. The apartments are already on the market. The cadastral split and the base deed are done. Each unit can be sold separately, but if someone wants the whole building, that works too.

 

SSY      This is the first project of Realiven, your new company. What is the vision?

JNM     Realiven sits between developer and property trader. After thirteen years at Inowai and two years running real estate for an industrial family at Unibra, I wanted to build something of my own. This project was personal at the start, but it gave me the appetite to do more. The full story is in the podcast.

 

Watch the full video

Jean-Nicolas Montrieux takes us through his first project as an independent developer. From the future garden to the rooftop studio. Three apartment types, one building, eighteen years in the making.

 

Listen to the podcast

In the full podcast episode, Jean-Nicolas talks about his career path from Inowai to Unibra to Realiven, why he decided to launch on his own, and how he sees the Luxembourg real estate market today.

Link here 👉 shesaidyes.lu/podcast/realiven-jean-nicolas-montrieux

 

👉 See Also :

Episode with Jean-Nicolas Montrieux on Realiven and the Luxembourg real estate market

Inspiring stories on real estate, design and architecture on SSY! podcast.

Discover more Real Estate Inspiration Stories on how people shape their homes.

 

🏡 Share this episode with someone who loves real estate, renovation projects, and the quiet patience of building something over eighteen years. Because a great building is never just walls. It is decisions, timing, and the people who make it happen.

 

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