continuer = True
liste = [1,2,3]
indexListe = 0

for qqch in machin:
    truc = fait_qqchose()

    for valeur in liste:
        if valeur == truc:
            continuer = False
            break

    if not continuer:
        break

    # Continuer l'execution de for qqch in machin.

# Fin de for qqch in machin.