Injective sheaves with values in a category.

In this thesis, we prove the following result: the category of sheaves with values in a Grothendieck category with a small generator and arbitrary products has enough injectives. The result remains valid if we replace the value-category by a Grothendieck category with a noetherian projective generator. The proofs are based on a theorem on transported structures which is due to J.M. Maranda