Please note that the sale of books to end customers in France is subject to the French law n°81-766 dated 10 August 1981 (called Lang Law) and related texts. As you know, according to these texts, the price of books is set by the Publisher or the Importer. Unless it is strictly justified by an exclusion or exception of the texts, retailers must comply with this unique price.
Please refer to applicable texts. You can for instance consult the complete text of Lang Law on Legifrance.gouv.fr at the following address: https://www.legifrance.gouv.fr/affichTexte.do?cidTexte=LEGITEXT000006068716&dateTexte=20170905
It is your responsibility to comply with all legal requirements and local laws. Amazon can remove uncompliant offers. Amazon cannot provide any legal advice. Please reach out to your legal advisor if you have any concerns or questions and generally to ensure compliance at all time with applicable texts, including with Lang law.