Résumé : TLM (Transaction-Level Modeling) was introduced to cope with the increasing complexity of Systems-on-Chip designs by raising the modeling level. Currently, TLM is primarily used for system-level functional testing and simulation using the SystemC C++ API widely accepted in industry. Nevertheless, TLM requires a careful handling of asynchronous concurrency. In this paper, we give a semantics to TLM models written in SystemC via a translation into the process algebra LOTOS, enabling the verification of the models with the CADP toolbox dedicated to asynchronous systems. Contrary to other works on formal verification of TLM models written in SystemC, our approach targets fully asynchronous TLM without the restrictions imposed by the SystemC simulation semantics. We argue that this approach leads to more dependable models.