Apex domains cannot have CNAME records.
Question and response
Question
dig oci-sa.fr. NS
Answer
oci-sa.fr. 5 NS dns1.oci-sa.fr.
oci-sa.fr. 5 NS dns2.oci-sa.fr.
Authority
The response has no authority records.
Additional
dns1.oci-sa.fr. 5 A 185.17.240.119
dns2.oci-sa.fr. 5 A 130.93.47.50
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0