Casa Alesan: How a Polish Investor Restored a Heritage Building in the Heart of Barcelona

In short. Casa Alesan is a restored heritage building on Paseo San Juan in Barcelona. Its transformation — from purchase in November 2020 to the sale of the last of 18 apartments in June 2023 — became a benchmark of a successful Barcelona property investment for a Polish businessman. Anteris led the project from a first conversation in 2019, through negotiation, due diligence, renovation, and full commercialisation, serving more than 200 pre-qualified buyers from 14 countries. The building won Barcelona’s 2024 Best Heritage Renovation award.

A relationship that started a decade earlier

In 2019 I met an entrepreneur in Poland whom I had known for more than ten years. It was essentially a catch-up — a “how are things” conversation. Seven or eight years earlier I had helped him with his son’s accommodation when the son was studying in Barcelona, and we had stayed in loose touch ever since.

Toward the end of the meeting, he said something I treated at the time as politeness: “let me know if anything interesting comes up on the investment side”. Honestly, I didn’t really expect him to be interested in a Barcelona investment. The Polish real estate market in 2019 was significantly more profitable, and the cycle was much shorter. On the other hand, returns are not everything. Portfolio diversification, geographic risk spread, and the desire to test yourself on an unfamiliar market all carry weight. That context would matter eighteen months later.

July 2020: an opportunity nobody was looking for

A few months after our conversation, the world fell into the pandemic. For many market participants this meant frozen investment decisions — uncertain horizons, travel restrictions, sector-wide paralysis. But there were also investors willing to act against the prevailing sentiment, on the conviction that an exceptional project will defend itself regardless of macro context.

In July 2020 we were brought an unusual file: a heritage building on Paseo San Juan — a beautiful boulevard in central Barcelona, although somewhat underrated compared to its more famous siblings Paseo de Gracia and Rambla Catalunya. An international group of investors that had bought the building in 2016 was deciding to exit. Worn down by the formalities of restoring a heritage property in Catalonia — a region where the question of independence kept resurfacing — and by a world in covid-era torpor, they had concluded it was a good moment to close their side of the project.

For us, this meant something rare: a heritage building in the heart of Barcelona, with full project documentation, ready to acquire, at a price that reflected the circumstances under which the sellers wanted to close.

Five minutes that triggered a three-year project

At that point we already had a professionally produced project video — a presentation tool whose creation had cost dozens of hours of work from graphic designers and architectural visualisation specialists. By the standards of the time, the presentation was striking enough that the Polish investor called me five minutes after I had sent the file by WhatsApp.

That is how Project Casa Alesan began.

Writing today “by the standards of the time”, I realise I am describing something only five years old as if it belonged to a different era. The video that cost several hundred hours of specialised work in 2020 could today — with the right craft — be assembled in one or two days with the help of artificial intelligence. The presentation ceiling rises; the entry threshold falls. But in July 2020, the existing tool was enough to close an investment decision in five minutes, with no need for the buyer to physically travel to Barcelona.

A multi-cultural transaction

The “we buy” decision was of course only the starting point for months of negotiation. Due diligence, dozens of hours in legal discussions over contract wording, debates about warranties, party responsibilities, disclosure scope — all of this in a setting where the geography of the parties was, to put it mildly, unusual:

• the buyer was a Polish businessman;
• part of the seller group was based in Israel;
• he property sat in Barcelona, under Catalan civil law;
• the lawyer representing our client was German;
• the whole process was coordinated by Anteris, operating in four languages.

A mix of legal cultures, expectations on guarantees, negotiation styles, and operational tempos is often the largest single source of delay in such transactions. A Polish businessman expects substance and closure; an Israeli seller will happily reopen topics that seemed settled; a German lawyer protects the systematic precision of every clause; a Spanish notary works to an administrative rhythm that has its own logic. Our role — beyond the conventional agency function — was to act as a moderator between these systems: translating not just language, but expectations.

The transaction closed in November 2020, after almost five months of negotiation.

A role extending beyond brokerage

Contrary to common perception, a real estate agency typically earns its fee at the notary signing — and that is usually where its role ends. With Casa Alesan we decided to operate differently. The client was in Poland, the sellers had dispersed, and the building required a comprehensive renovation that combined preservation of heritage elements under conservation supervision with full modernisation of systems, apartment layouts, and common areas.

Anteris participated in every post-purchase stage:

• selecting the general contractor and the project firm;
• coordinating with the heritage conservator and the municipal administration;
• decisions on finish quality and apartment layout;
• preparation of marketing materials for each apartment;
• the sales campaign targeting buyers worldwide;
• after-sales support, including formalities at the Spanish Registro de la Propiedad.

This level of involvement goes beyond a “transactional brokerage” model. For the investor, it meant no need to build a parallel operational structure in Barcelona — a condition that, for a businessman whose primary activity remained in Poland, was the boundary condition for committing to a foreign property investment in the first place.

Three years, 18 apartments, 14 nationalities

The full project — from acquisition to the sale of the last apartment in June 2023 — lasted approximately three years. It closed as a success on every meaningful measure:

• The restored building was awarded Barcelona’s 2024 Best Heritage Renovation Project;
• All 18 apartments and two commercial units were sold;
• Buyers came from 14 different nationalities — from Argentina to the Philippines;
• In the sales process, Anteris served more than 200 pre-qualified clients, selected from nearly 1,800 leadsgenerated by the marketing campaign.

For a building of this size, that geographic spread of buyers is uncommon. It is explained by the nature of the product: a heritage building in the centre of Barcelona, restored with full historical character intact, is today one of the few European assets in which a buyer simultaneously acquires cultural value, a residence for daily use, and an investment with capital-preservation logic.

What Casa Alesan says about the role of an agency in 2026

Every transaction in the premium property market has its own demands. Casa Alesan made one point particularly clear in the context of the 2026 market: in cross-border transactions — especially those where the parties operate under different legal and cultural systems — the value an agency adds is defined less by access to inventory and more by the capacity to run a process in its full, complicated geometry. Translating language and translating expectations are two distinct competencies. In Casa Alesan, both proved as essential as the quality of the building itself.

For an international investor, the conclusion is straightforward: investing in premium property abroad does not require building a dedicated operational structure in the destination country — provided the local partner understands both the market and the specificity of the client. That kind of role demands long-tenure presence, fluency across the jurisdictions involved, and access to the professional network that completes transactions.