French law is fundamentally different from English law; children of co- owners of French property, whether the co-owners are French or not, have entrenched rights to inherit a proportion of a parent's share of the property and, in the absence of a carefully prepared agreement to the contrary, a buyer may discover that child number three of his once best mate will have every right to force a sale at any stage. Automatic devolution of the property into the hands of the survivors of the original co-owners can only be achieved by the insertion of a particular clause in the purchase contract, a clause which will often be unfamiliar to the notaire with whom the buyer is obliged to deal. Corporate ownership may sometimes help, although the costs of setting up a corporate structure may prove prohibitive in properties of relatively low value.
A can of worms? Ideally (and usually) not, so long as the long-term implications of the venture are thought through.