This paper introduces a methodology to perform formal verification of floating-point C programs. It extends an existing tool for the verification of C programs, Caduceus, with new annotations specific to floating-point arithmetic. The Caduceus first-order logic model for C programs is extended accordingly. Then verification conditions expressing the correctness of the programs are obtained in the usual way and can be discharged interactively with the Coq proof assistant, using an existing Coq formalization of floatingpoint arithmetic. This methodology is already implemented and has been successfully applied to several short floatingpoint programs, which are presented in this paper.