Abstract : Component-based Engineering aims at providing a modular means to specify a wide range of applications. The idea is to promote a clean separation of concerns, and thus reusability, in order to ease the burden of software development and maintenance. The specification of such component models however, tends to be informal, leaving their inherent ambiguities open to interpretation. In this paper we present our ongoing work towards a formal specification of the Fractal Component Model mechanized in the Coq Proof Assistant. An operational semantics for building component-based architectures is presented, along with its compliance with the Fractal specification.