Apex domains cannot have CNAME records.
Question and response
Question
dig static-ip.oleane.fr. NS
Answer
static-ip.oleane.fr. 5 NS ns1.oleane.net.
static-ip.oleane.fr. 5 NS ns0.oleane.net.
Authority
The response has no authority records.
Additional
ns0.oleane.net. 5 A 194.2.0.30
ns1.oleane.net. 5 A 194.2.0.60
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0