Résumé
I present the first constraints on decaying cold dark matter (DCDM) models thanks to the effective field theory of large-scale structure (EFTofLSS) applied to BOSS-DR12 data. I consider two phenomenological models of DCDM: i) a model where a fraction$f_{\rm dcdm}$of cold dark matter (CDM) decays into dark radiation (DR) with a lifetime$\tau$ ; ii) a model (recently suggested as a potential resolution to the$S_8$tension) where all the CDM decays with a lifetime$\tau$into DR and a massive warm dark matter (WDM) particle, with a fraction$\varepsilon$of the CDM rest mass energy transferred to the DR. I discuss the implications of the EFTofLSS constraints for the DCDM model suggested to resolve the$S_8$tension.