Apex domains cannot have CNAME records.
Question and response
Question
dig ciel-clair.com. NS
Answer
ciel-clair.com. 3 NS ns-692.awsdns-22.net.
ciel-clair.com. 3 NS ns-705.awsdns-24.net.
ciel-clair.com. 3 NS ns-1355.awsdns-41.org.
ciel-clair.com. 3 NS ns-1516.awsdns-61.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0