Splitting an apartment in Paris: profitable but heavily regulated

An 80 m² apartment at 9,000 euros/m² in the 10th arrondissement: 720,000 euros. Rented as a single unit at 2,000 euros/month, the gross yield reaches 3.33%. Split into two 40 m² units each rented at 1,200 euros/month, the gross yield rises to 4%. One extra percentage point of yield, or 4,800 euros/year in additional income. Over twenty years, the cumulative difference exceeds 96,000 euros. Apartment splitting is one of the most profitable strategies in Parisian property investment, and one of the most fraught with regulatory hurdles.

Why does splitting a flat pay more in Paris?

Because rent per square metre increases as surface area decreases: in Paris, an 80 m² flat rents for 25 to 28 euros/m² furnished, a 40 m² for 30 to 35 euros/m², and a 20 m² studio reaches 38 to 45 euros/m². Two small units therefore earn mechanically more than one large one, for the same total surface.

This gradient is universal and enduring: it reflects the structure of Parisian demand, dominated by one and two-person households who represent over 70% of tenants.

By splitting a large unit into two smaller ones, the investor captures this differential. The additional rental income must cover the splitting costs (works, compliance, administrative procedures) and compensate for the additional constraints: two tenants instead of one, potentially higher turnover, doubled management charges, and two EPCs instead of one.

What rules must you follow to split a flat in Paris?

Five obstacles stack up: the minimum surface of 9 m² and 20 m3 per unit created, co-ownership approval by the absolute majority of article 25, a prior works declaration at the town hall, an individual EPC for each unit created, and compliance with decency standards. Co-ownership approval is the most frequent blocking point, and a non-division clause in the regulations makes splitting impossible.

The minimum surface per newly created unit is 9 m² of habitable surface and 20 m3 of volume (article 4 of the decree of 30 January 2002). In practice, creating a 9 m² unit is impractical: virtually unrentable, unsellable, ineligible for bank financing. Most serious investors aim for a minimum of 14 to 16 m² per unit to preserve rental attractiveness and resale value. For an 80 m² split into two, the target of 40 m² per unit is comfortable and poses no surface area issues.

That co-ownership approval is the most underestimated step of the whole pathway. Splitting changes the number of units in the co-ownership, which requires a vote at the general meeting by the absolute majority of article 25 (majority of all co-owners’ votes, present or absent). In practice, obtaining this majority is as much a political exercise as a legal one: you must convince co-owners that the split will not degrade quality of life in the building or devalue their own units.

Many Parisian co-ownerships include a non-division clause in their regulations: an outright prohibition on any splitting. This clause, often inherited from the building’s original division deed (1950s-1970s), is legally binding and can only be modified by a unanimous vote at the general meeting. In practice, it is virtually immovable. The first step in any splitting strategy is therefore reading the co-ownership regulations: a document our property hunters systematically review before the first viewing.

A prior works declaration at the town hall is mandatory whenever the split creates a new dwelling. The Cerfa form is filed at the arrondissement town hall, with a scaled plan of the units created, a description of the planned works, and the resulting habitable surfaces. Processing time is one to two months. If the split involves a facade modification or the creation of a separate entrance, a building permit is required, with a 2 to 3-month timeline and significantly heavier documentation requirements.

An individual EPC is mandatory for each unit created. A critical point often overlooked: splitting an apartment with a good overall D rating can produce two units, one of which is rated E or F. The interior unit, the one without a window facing outside or with a single north-facing window, is systematically rated lower. An F-rated unit will no longer be rentable from 2028, which would make the split partially unworkable.

Finally, compliance with decency standards requires that each unit has an electrical system conforming to the NF C 15-100 standard, a drinking water supply and hot water, wastewater drainage connected to the collective network, adequate ventilation, and a heating system. Each unit must also have its own water and electricity meter.

Discover how Home Select can support you

How much do splitting works cost?

The realistic total budget for splitting into two units is between 30,000 and 50,000 euros. It breaks down into separate meters (5,000 to 10,000 euros), a complete shower room (15,000 to 20,000 euros), an equipped kitchenette (5,000 to 8,000 euros), sound insulation between units (3,000 to 6,000 euros) and electrical and plumbing compliance (3,000 to 5,000 euros).

Creating separate meters (electricity and water) is the essential technical prerequisite. Each unit must have its own meter so the tenant pays their own consumption. The cost varies between 5,000 and 10,000 euros depending on the building configuration, the distance to the main electrical panel, and the need for new riser pipes.

Creating an additional kitchen or bathroom is the heaviest cost item. A complete shower room (shower, basin, WC) with plumbing connections, electrical supply, tiling and fixtures: 15,000 to 20,000 euros. An equipped kitchenette (sink, hob, fridge, worktop, connections): 5,000 to 8,000 euros. These amounts include labour but not contingencies, and in older Parisian buildings, contingencies are the rule, not the exception. Lead pipes to replace, deteriorated waste stacks, impossible cable routing through load-bearing walls, concrete slabs to drill for drainage: every renovation in an older building brings at least one unpleasant surprise.

Sound insulation between the two units is both a legal obligation (the decency decree imposes a minimum acoustic insulation level between dwellings) and an absolute necessity. Two tenants separated by a simple 72 mm plasterboard partition is a guaranteed neighbour dispute and tenants who leave within the year. Proper insulation (double partition with 45 mm mineral wool minimum, acoustic ceiling doubling if needed) costs 3,000 to 6,000 euros depending on the separation area.

Electrical compliance (panel, sockets, circuit breakers to NF C 15-100) and plumbing (connections, drainage, ventilation) adds 3,000 to 5,000 euros for the operation as a whole.

Added together, these items produce exactly the 30,000 to 50,000-euro realistic budget. Our rule at Home Select, forged through experience with hundreds of renovations: multiply the first quote by 1.3 to account for contingencies. A first quote at 35,000 euros becomes a prudent budget of 45,500 euros.

What does splitting an 80 m² flat in the 10th actually return?

On an 80 m² flat bought at 720,000 euros and split for 45,000 euros of works, the net yield rises from 2.30% to 2.64%, or 3,833 euros of additional net income per year. The works investment is repaid in 11.7 years, and the cumulative benefit reaches 76,660 euros over twenty years.

The detail: an 80 m² apartment on the 3rd floor of a building in the 10th arrondissement, purchased at 720,000 euros (9,000 euros/m²). Notaire fees: 54,000 euros, or 7.5% of the price. Splitting works into two 40 m² units: 45,000 euros (prudent budget, first quote increased by 30%). Total investment: 819,000 euros.

As a single furnished unit, the property rents at 2,000 euros/month (25 euros/m²), or 24,000 euros/year. Annual charges (co-ownership fees 2,000 euros, property tax 800 euros, non-occupant insurance 200 euros, management 1,920 euros, maintenance 600 euros, vacancy 667 euros) total 6,187 euros. Net income: 17,813 euros. Net yield on total investment (774,000 euros excluding splitting works): 2.30%.

Split into two furnished 40 m² units, each rents at 1,200 euros/month (30 euros/m²), a total of 28,800 euros/year. The gross gain from splitting is 4,800 euros/year. Charges increase partially: two management contracts (2,304 euros), two vacancy provisions (800 euros), but stable co-ownership fees (2,000 euros), stable property tax (800 euros), slightly higher insurance (250 euros), doubled maintenance (1,000 euros). Total charges: 7,154 euros. Net income: 21,646 euros. Net yield on total investment (819,000 euros including works): 2.64%.

The annual gain from splitting is therefore 3,833 euros in net income. The return on the works investment (45,000 euros) is reached in 11.7 years: a long but acceptable timeframe for an investment planned over 20 years. Over that period, the cumulative benefit of splitting reaches 76,660 euros, a return of 1.7 times the cost of works.

Under the LMNP (furnished non-professional landlord) regime with actual expenses, depreciation applies to a higher amount (the property plus splitting works, depreciable over 10 to 15 years). The tax result is negative for the first 10 to 12 years for both units combined. Net-net LMNP yield: 2.64% versus 2.30% without splitting.

In which Paris arrondissements is splitting most favourable?

The 10th, 11th, 18th, 19th and 20th arrondissements concentrate the favourable configurations: large 19th-century floor plates and a young rental demand that absorbs 30 to 45 m2 units. The 20th, with its more accessible prices, offers the best gross margins.

The 10th arrondissement has a concentration of large floor plates (60-120 m2) in 19th-century buildings, with a young and mobile tenant population that easily absorbs 30 to 45 m2 surfaces. The 11th has a similar profile between Bastille and Belleville. The 18th (Marcadet, Poissonniers) and the 19th (Buttes-Chaumont, Crimée) contain buildings whose large apartments lend themselves to splitting after renovation. The 20th, with its more accessible prices (8,400 euros/m2), offers the best gross margins.

Why have the co-ownership regulations analysed before buying?

Because a non-division clause in the regulations outright forbids splitting, and this check takes five minutes before the first viewing. It is the key to a successful operation: it saves months of unnecessary procedures and avoids ending up with a property that is oversized for rental.

An experienced property hunter therefore systematically checks, before any viewing, whether the regulations allow splitting or contain a non-division clause.

Our property hunters cross-reference this information with the history of general meetings (have splits been voted on in the past?), the building’s technical condition (water risers, electrical capacity) and the apartment’s layout (possibility of creating two viable units with shared or independent access).

Across the 1,200+ mandates completed, the successful splitting operations share one common feature: the analysis was done beforehand, not after purchase. An investor who buys an 80 m2 flat hoping to split it and then discovers the co-ownership refuses is left with an oversized property for rental and an underperforming investment. This is a scenario we have seen too often, and one that our upfront involvement systematically prevents.

Discuss your investment project with us