Introduction historique au droit by Open access available to all with access to the internet
The Franks were a Germanic tribe which occupied northern Gaul (in modern terms: France & Belgium, with parts of Italy, Netherlands and Germany) after the end of the Roman Empire.
The Pactus Legis Salicae is attributed to Clovis I; Lex Salica Karolina is the reissue under Charlmagne.
The Laws of the Salian Franks by Droit coutumier/Droit feudal
At the beginning a tapestry of laws of localities, from mid (15th there are steps being made towards a "modern" national legal system.
A north-south divide (La Rochelle-Geneva) can be traced in early French law. In the south (sometimes called "le pays de droit ecrit") the influence of Roman law remained strong; to the north the influence of the Germanic system was stronger.
In 1454, ordinance of Charles VII decreed that a written record should be made of all existing oral local custom. (Coutumiers term for collections of Coutumes locales.)
Under Francois I (and Chancellier Poye) the Ordonnance de Villers-Cotterêts (1539) introduced reforms across a wide range of legal matters, including criminal procedure.
Gallica - the online catalogue for the digitised collection of the Bibliotheque Nationale de France - is an excellent place to find early editions of the various coutumiers available on the free web. The Advanced Search Screen allows you to do a subject search by Droit coutumier - France then specific regions eg Droit coutumier - France - Normandie.
Some subject searches to try in SOLO:
Customary law - France
Law France History
Law France Sources
Feudal Law -France
Land tenure -- Law and legislation -- France -- Early works to 1800
Feudalism - France
Take note of the location in your search results, you will probably find that most are in other parts of the Bodleian, not the Law Library. However, the Law Bod does have some titles which may help, such as those below:
Custom, Law, and Monarchy by Open access titles available to all with access to the internet
Les décisionnaires et la coutume Contribution à la fabrique de la norme by En bon trayn de justice Les grands jours du Parlement de Paris au lendemain de la guerre de Cent Ans by Charondas Le Caron, Pandectes du droit Français (1596) (read online via BVH see link below)
Coquille, Institution au droict des françois (1607) (read online via Gallica see link below)
de L’Hommeau, Maximes généralles du droit François (1610) (read online via Gallica see link below)
(16th stirrings of the concept of codification
Charles Demoulin (1500-1566)
Code Henri III (1586)
(17th precursors
Code Marillac (1629)
Grandes Ordonnances of Louis XIV (1667 - 1681 Colbert)
From 1697 onwards, national/royal/customary law was taught at French universities (in addition to canon & Roman law which had been taught from the beginning).
(18th precursors
Ordonnances edited by Chancelier d’Aguesseau (1731 - 1747)
The Royal Financial Administration and the Prosecution of Crime in France, 1670-1789 by Assemblée nationale constituante (17 juin 1789-30 septembre 1791)
Assemblée nationale législative (1er octobre 1791-21 septembre 1792)
1804 reorganisation of French law faculties
The Abolition of Feudalism peasants, lords, and legislators in the French Revolution by 
La Révolution française face au système judiciaire d'Ancien Régime by Projet d'Olivier 1789
1791 Revolutionary penal & criminal procedure codes
Plan Durand Maillance 1793
Projets Cambacérès1793, 1794
1795 Code of Delicts & penalties
Projet Cambacérès 1796
Projet Jacqueminot 1799
Projet of the Year VIII (1800)
Networks of interest
" The Maison Française is governed by three major French institutions:
The Université de Paris: The MFO is an academic institution that facilitates communication between French universities and the University of Oxford.
The CNRS: The MFO is a research centre in humanities, social sciences and natural sciences.
Le Ministère des Affaires étrangères: The MFO is part of the French research institutes abroad (IFRE), ruled by the Ministry of Foreign Affairs and it promotes French culture and language. ...
The Maison Française is not only for members of the University of Oxford! It is a landmark for the French, French-speaking, and francophile community of Oxford, with free French film screenings (See the catalogue).
The library, with workspaces, a large selection of French works, a youth space, as well as DVDs, is accessible to everybody."