For an introduction in English see Chapter 8 of book below:
National treaty law and practice by The official text of any treaty to which France is a signatory is that published in the Journal Officiel. (JO from 1990 available via Legifrance.)
The Ministère des Affaires étrangères hosts a free online database Base Pacte This will provide at least the following: title, date of signature and publication details. A selection of treaties are available in full-text. There are separate search screens for bilateral and multilateral treaties.
(It is also possible to search for those treaties to which France is not a signatory, but is the official depository.)
Both the Conseil Constitutionnel and the Conseil D'État have considered the relationship between treaty and national laws
Décision 1974-54 DC, 15 January 1975 (the jurisdiction to examine a conflict between a parliamentary act and a treaty)
Décision 2004-496 DC, 10 June 2004 (EU directive and French law)
Décision 2006-540 DC, 27 July 2006
CE 20 octobre 1989 Nicolo (analysis) (conformity of French statute with the Treaty of Rome)
CE, 8 February 2007 (analysis)