No. Unlike partitions following legal separation, divorce or the dissolution of a civil partnership (PACS), cohabitation does not benefit from the preferential partition duty of 1.10% on the net assets divided. The applicable rate between cohabitants is 2.50%, or even 5.80% where balancing payments are made (Arts. 746 and 747 of the French Tax Code).
Reminder: Partition consists of distributing assets among co-owners.