Apex domains cannot have CNAME records.
Question and response
Question
dig eolas.fr. NS
Answer
eolas.fr. 5 NS ns02.eolas.fr.
eolas.fr. 5 NS ns01.eolas.fr.
eolas.fr. 5 NS ns03.eolas-dns.eu.
Authority
The response has no authority records.
Additional
ns01.eolas.fr. 5 A 178.237.104.1
ns02.eolas.fr. 5 A 178.237.108.1
ns03.eolas-dns.eu. 5 A 51.83.201.211
ns01.eolas.fr. 5 AAAA 2a00:4280:100:d00:33ab:7bbd:9949:389
ns02.eolas.fr. 5 AAAA 2a00:4280:100:e00:833b:4c9:5cf8:8ea0
ns03.eolas-dns.eu. 5 AAAA 2001:41d0:a800:801:f592:7c6d:e501:b473
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0