The Interuniversity Attraction Pole CORES, which funded my work, meant "to establish and compare the regional trajectories of change and development in four specific ancient regions", thanks to the "explanatory power of large windows in time". The observation of monetary practices through a temporal window of more than a millennium could only enrich our understanding of these practices and of their evolution. So I made the long-term the guiding line of my thesis. To make the most of this long-term approach, I opted for a thematic method, where each question has been dealt with throughout the different periods, so as to highlight the relevant continuities and breaks. The functions of coinage and their evolution over time form the central topic of my research. The (mainly political) authorities produced coins in order to fulfill functions to their benefit. These functions form an essential factor in determining the volume and quality of their coin production. Stocks of metal, personnel, equipment and know-how are needed to start and maintain such a production. Throughout the Gallic, Gallo-Roman and Frankish periods, I tried to better identify those responsible for coin issues and to evaluate the resources at their disposal to produce them. On the other hand, I have tried to identify a maximum of functions performed by coins for the benefit of their producers and then for the public, by implementing the different types of sources available: the coins themselves, archaeological contexts, literature and epigraphy. The choice of the long term as a guideline and the questions resulting from this approach allowed several studies to be carried out for the first time. Using the French, German and English sources, I gathered the corpus of the Celtic means of coin production. The mentions of money in some ancient texts had already been studied, but never on such a scale and over such a long period of time. The corpus of texts I assembled will certainly be useful. Most of the numismatists considered the fiduciarity of ancient coinages as obvious, while for others, the exchange value of ancient coins could not be greater than the value of their metal content. The long-term guideline has allowed me to explore, in greater depth, the sources that shed light on this problem, and to demonstrate that all ancient coins contained a fiduciary part. My thesis, to be published, will now serve as a platform and reference for further research. This will spare future researchers the need to consult numerous books and articles, to be replaced by the corpus of documents I have collected and reviewed.