To sell a property, the unanimity of the co-owners is required. However Article 815 of the French Civil Code stipulates that, “no one may be forced to remain in the state of undivided ownership and partition may be initiated at any time, unless it has been suspended by judgment or agreement.”
Thus a co-owner may exit from undivided ownership at any point in time. There are three possibilities:
by selling their share to another co-owner,
by selling the property: co-owners seeking to sell should represent at least 2/3 of the undivided rights,
by selling their share to a third party.
In your case, the third possibility remains: sell your 20% of undivided share in the property to Squat Solutions. Learn more about the purchase of undivided shares.