Apex domains cannot have CNAME records.
Question and response
Question
dig shaftinc.fr. NS
Answer
shaftinc.fr. 4 NS ns1.shaftinc.fr.
shaftinc.fr. 4 NS ns2.bortzmeyer.org.
shaftinc.fr. 4 NS ns2.shaftinc.fr.
shaftinc.fr. 4 NS ns1.bortzmeyer.org.
Authority
The response has no authority records.
Additional
ns1.shaftinc.fr. 4 A 51.178.53.118
ns1.bortzmeyer.org. 4 A 80.77.95.49
ns2.shaftinc.fr. 4 A 136.244.112.196
ns2.bortzmeyer.org. 4 A 172.104.125.43
ns1.shaftinc.fr. 4 AAAA 2001:41d0:404:200:0:0:0:49e1
ns1.bortzmeyer.org. 4 AAAA 2602:fbb1:1:245b:0:0:0:42
ns2.shaftinc.fr. 4 AAAA 2a05:f480:1c00:28a:5400:2ff:fee7:316f
ns2.bortzmeyer.org. 4 AAAA 2400:8902:0:0:f03c:91ff:fe69:60d3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0