The purpose of the present thesis is to let French lawyers know which step they need to take in order to best assist their client in securing a more solid investment. Lenders want to be protected. Lenders want to be sure that they can use the intellectual property rights in a commercial environment free from superior claims by third parties. In other words, a lender who provides a large loan to a borrower wants to know how and where its security interest will be perfected and what is the best way for him to have priority over other claims. This thesis also will first examine the classification of collateral and represents an effort to summarize whether a state or a federal filing is required to perfect a security interest. Second, the thesis will examine the main issues arising out from the priority rules in the area of bankruptcy. Finally, it will address the different proposals suggested in order to have a clarification of the actual system.