My spouse and I have divorced. During our marriage, we bought a house that we wish to keep. Are we required to establish a co-ownership agreement ?

No. Regardless of the origin of the co-ownership (whether from an inheritance or a divorce, for example), a co-ownership agreement is always optional. However, since decisions must generally be made unanimously by all co-owners, which can be a source of difficulties, the agreement allows you to organize in advance the modalities of exercising the owners' rights: enjoyment of the property, appointment of a manager, etc.