Apex domains cannot have CNAME records.
Question and response
Question
dig edoc.fr. NS
Answer
edoc.fr. 5 NS dns104.ovh.net.
edoc.fr. 5 NS ns104.ovh.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0