Old French law

Old French law, referred to in French as l'Ancien Droit, was the law of the Kingdom of France until the French Revolution. In the north of France were the Pays de coutumes ('customary countries'), where customary laws were in force, while in the south were the Pays de droit écrit ('countries of written law'), where Roman law had been paramount. Roughly speaking, the line separating the two areas was the river Loire, from Geneva to the mouth of the Charente, although this was not a firm border between the two categories of law. As worded by George Mousourakis, "in both zones, the law in force also included elements derived from royal, feudal, and canonical sources."

Pays de coutumes

In the north existed a variety of customs "with a Frankish-Germanic character."

In the tenth and eleventh centuries, as the Carolingians gave way to the Capetians, Frankish law broke up into many different systems, according to the territories, some extremely small, won by princes and prelates.

The coutumes were asserted and enforced under feudalism during the Middle Ages and in the early modern period by the French kings and their vassals, especially in the lands of the Île-de-France, to the exclusion of Roman law. A number of regional coutumes starting from the 13th century: e.g. the Coutumes de Beauvaisis, compiled by Phillipe de Remy. By the 16th century, the Coutume de Paris, first published in 1510, eventually extended to all of the Parlement of Paris' jurisdiction and beyond in cases of any alleged lacunae in the local customs. Antoine Loysel published a work of 958 legal maxims developed over a period of 40 years distilling the coutumes in his Institutes coutumières: Ou manuel de pluſieurs & diuerſes reigles, ſentences, & Prouerbes tant anciens que modernes du Droic‍t Couſtumier & plus ordinaire de la France, in 1607. Further development of customary law had been halted by the late 16th century.