Apex domains cannot have CNAME records.
Question and response
Question
dig free.fr. NS
Answer
free.fr. 4 NS freens2-g20.free.fr.
free.fr. 4 NS freens1-g20.free.fr.
free.fr. 4 NS freens3-scw.free.fr.
Authority
The response has no authority records.
Additional
freens1-g20.free.fr. 4 A 212.27.60.19
freens2-g20.free.fr. 4 A 212.27.60.20
freens3-scw.free.fr. 4 A 51.159.199.148
freens1-g20.free.fr. 4 AAAA 2a01:e0c:1:1599:0:0:0:22
freens2-g20.free.fr. 4 AAAA 2a01:e0c:1:1599:0:0:0:23
freens3-scw.free.fr. 4 AAAA 2001:bc8:1203:102:0:0:0:0
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0