Saint-Vallier was consecrated bishop at Saint-Sulpice on January 25, 1688 and allowed his predecessor to go back to Canada. However, this would prove to be detrimental for him as upon his return in the summer of 1688, there was a disagreement between him and the seminary of Quebec. Three priests and the Bishop Laval conspired together in order to undermine Saint-Vallier's authority and "three quarters of the clergy in Canada […] already escaped the direct authority of the bishop, who found himself, in addition, obliged to share his jurisdiction over his own secular clergy with his seminary."