France contribute to the ROSETTA mission at three levels :

Through its participation to the ESA obligatory program : thus, French industry intervenes in the realization of the main satellite (particularly ASTRIUM).
Through instrumental participations to the payloads, for the Orbiter as well as for the Lander.
Through a participation to the engineering, to the development, to the tests and lander operations.

In parallel to the national industry developing one part of the main satellite under ESA contract, the other French activities are managed by the Toulouse center of the French National Space Agency (Centre National d'Etudes Spatiales).

The project team that works there rely on :

for instrumental participations, the following laboratories of the Centre National de la Recherche Scientifique (CNRS), the Toulouse Paul Sabatier University and the Paris Observatory :

For technical participations, the CNES technical services and the industry (SOREP, SAFT, STEEL, CS, REALIX, GFI, THALES ...).