To be exact according to Art. 815 of the Civil code: "Nul ne peut être contraint à demeurer dans l'indivision et le partage peut toujours être provoqué, à moins qu'il n'y ait été sursis par jugement ou convention." That means that anyone part in an indivision (whatever his/her share) can go to Court to "get out" (i.e. force the sale to recup the value of his/her part). This is a very solid right and the Court should not refuse it unless it is abused (e.g. to cause harm) but keep in mind that, in practice, it will probably take quite a long time to obtain satisfaction...