Apex domains cannot have CNAME records.
Question and response
Question
dig thalos.fr. NS
Answer
thalos.fr. 4 NS dns1.thalos.fr.
thalos.fr. 4 NS dns2.thalos.fr.
Authority
The response has no authority records.
Additional
dns1.thalos.fr. 4 A 173.246.103.207
dns2.thalos.fr. 4 A 62.193.60.39
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0