Method
Bedrooms of different sizes: should everyone pay the same rent?
No, and nothing requires it. Room size justifies a gap, but only on the portion of rent matching the bedrooms: common areas are split equally, since their use does not depend on room size. Applying the gap to the whole rent charges the big room twice over.
What justifies a gap, and what does not
Private floor area is the one criterion everyone accepts without argument, because it can be measured. A bathroom reachable only from one bedroom, a private balcony or the absence of a window are commonly added, with gaps in the order of ten to fifteen per cent. By contrast, seniority in the flat, income level or going home most weekends do not justify a rent gap: those are arrangements, and they get renegotiated every time someone's situation changes, which makes them unstable.
The mistake that charges the difference twice
The most common approach divides the whole rent in proportion to bedroom size. It looks fair and it is not: the kitchen, living room and hallway serve the person in nine square metres exactly as much as the person in eighteen. Splitting those by bedroom size charges the same difference a second time. In a flat where common areas are half the floor space, the real gap between two bedrooms is half of what a raw per-square-metre split produces.
The method that holds up
Split the rent in two in proportion to floor area: the common areas share and the bedrooms share. Divide the first equally between flatmates, the second in proportion to each bedroom's size, adjusted for its perks and drawbacks. Add the two together. In a sixty square metre flat at nine hundred euros, with bedrooms of ten and twenty square metres and thirty square metres of common areas, you get 375 and 525 euros, where a raw split would have given 300 and 600.
Put the agreement in writing
No rule prescribes how flatmates split rent: the lease sets what is owed to the landlord, the internal share is your own agreement. It does not need a solicitor, but it needs to exist somewhere other than in everyone's memory. A message in the group chat, stating the method and the date, is enough to avoid the argument a year later, especially when someone moves out.
Key points
- No French law prescribes how flatmates divide rent between themselves: only the lease binds the signatories to the landlord.
- Common areas in a flatshare are split equally between occupants, because their use does not depend on bedroom size.
- Splitting an entire rent by bedroom size charges the difference twice, once on the bedroom and once on the common areas.
- A bedroom with a private bathroom is commonly valued ten to fifteen per cent above a room of the same size without one.
- A room with no window to the outside does not count as a habitable room under French decency rules, which disqualifies it as a main bedroom.
- Habitable floor area under the French Carrez law excludes any space with a ceiling height below 1.80 metres.
Frequently asked questions
Can flatmates pay different rents by room?
Yes. The lease sets the total owed to the landlord; how flatmates divide it is a private agreement. Write it down, even in a group chat.
Does a shared bathroom count as common area?
Yes, if it is shared. Only a bathroom reachable solely from one bedroom counts as that room's private floor area.
Should a balcony count towards floor area?
A private balcony justifies a modest premium, around five per cent, but it does not add to habitable floor area, which counts indoor space only.
What if the rooms are the same size but one is brighter?
A gap is defensible if everyone agrees, but it is hard to quantify objectively. Many flatshares prefer to draw lots for the rooms and pay the same share.