[en] We study a Feigin-Fuchs construction of conformal field theories based on a GxG/G coset space, in terms of screened bosons and parafermions. This allows to get the formula for the conformal dimensions of primary operators. Lists of modular invariant partition functions for the SU(3), SO(5) and G₂ Wess-Zumino-Witten models are given. Besides the principal series of diagonal invariants, a complementary series exists for SU(3) and SO(5), which is due to the outer automorphism of the Kac-Moody algebra. Moreover, exceptional solutions appear at level 5, 9, 21 for SU(3), at level 3, 7, 12 for SO(5) and at level 3, 4 for G₂. From these modular invariants, those for the corresponding G_N x G_L/G_N+L models are constructed. (orig.)