Subventions/aide publique

Does any of you know where I can find information about the legal framework of subsidies in France? I am writing my master thesis about the principle of legal expectations in the Netherlands, Belgium and France, but it turns out to be quite difficult to find information about France (I found the title book by Serge Huteau, 'Les subventions, aspects juridiques, comptables et fiscaux', but this book is nowhere to be bought anymore).

What I want to know is what the legal basis for the allocation of subsidies in France is (is this based on a law or are all the subsidies given on the basis of a contract between the government and the receiver?) and if/how the recovery of subsidies (in case the receiver has not complied with the conditions) is regulated. Do the government bodies have any discretion when allocating and recovering the subsidies or are they obliged to recover?

If you have any information for me, please let me know!