  In the presence of a low scale seesaw of type I + III, flavor violating
effects in the leptonic sector are expected. Their presence in the charged
sector is due to the mixing of the fermionic vector-like weak triplets with the
chiral doublets, which cause non-universality of the tree-level Z coupling. We
investigate the bounds on the Yukawa couplings which are responsible for the
mixing and present the results for two minimal cases, a fermionic triplet with
a singlet or two fermionic triplets. Different channels for these processes are
considered and their current and future potential to probe these couplings is
discussed.
