Apex domains cannot have CNAME records.
Question and response
Question
dig bsiplabteamsbte.fr. NS
Answer
bsiplabteamsbte.fr. 5 NS ns1ent.bouygtel.net.
bsiplabteamsbte.fr. 5 NS ns2ent.bouygtel.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0