  In this thesis, we study the structure of Group Field Theories (GFTs) from
the point of view of renormalization theory. Such quantum field theories are
found in approaches to quantum gravity related to Loop Quantum Gravity (LQG) on
the one hand, and to matrix models and tensor models on the other hand. They
model quantum space-time, in the sense that their Feynman amplitudes label
triangulations, which can be understood as transition amplitudes between LQG
spin network states. The question of renormalizability is crucial if one wants
to establish interesting GFTs as well-defined (perturbative) quantum field
theories, and in a second step connect them to known infrared gravitational
physics. Relying on recently developed tensorial tools, this thesis explores
the GFT formalism in two complementary directions. First, new results on the
large cut-off expansion of the colored Boulatov-Ooguri models allow to explore
further a non-perturbative regime in which infinitely many degrees of freedom
contribute. The second set of results provide a new rigorous framework for the
renormalization of so-called Tensorial GFTs (TGFTs) with gauge invariance
condition. In particular, a non-trivial 3d TGFT with gauge group SU(2) is
proven just-renormalizable at the perturbative level, hence opening the way to
applications of the formalism to (3d Euclidean) quantum gravity.
