Analyse the variance decomposition

Bonjour à tous,
s’il vous plait je voudrais savoir comment faire l’analyse de la décomposition de la variance sur dynare.

That depends on the type you need. The unconditional variance decomposition (i.e. at horizon infinity) is printed whenever you request theoretical moments (periods=0). The conditional one is triggered via conditional_variance_decomposition=[x1, x2] where the x denote the forecast horizon. See the manual for details.