Apex domains cannot have CNAME records.
Question and response
Question
dig france-competences.info. NS
Answer
france-competences.info. 5 NS ns-1987.awsdns-56.co.uk.
france-competences.info. 5 NS ns-1079.awsdns-06.org.
france-competences.info. 5 NS ns-381.awsdns-47.com.
france-competences.info. 5 NS ns-572.awsdns-07.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0