Résumé : This dissertation focuses on the relationship between the law and Christian ideals during the high middle ages, especially from the mid-eighth to the mid-ninth c. How did Christianity and its models influence the making of the law under the Carolingians ? The main and central concept is, in fact, the religiosity of the law. More precisely, this research focuses on one specific matter ; transgressing sexual rules. Based on normatives sources (capitularies), this research aims to discuss how and to what extent Christian ideas were used while publishing the laws concerning incest, adultery and fornication