Apex domains cannot have CNAME records.
Question and response
Question
dig lb.fr-par.scw.cloud. NS
Answer
lb.fr-par.scw.cloud. 5 NS ns1.online.net.
lb.fr-par.scw.cloud. 5 NS nsele1.online.net.
lb.fr-par.scw.cloud. 5 NS nsele2.online.net.
lb.fr-par.scw.cloud. 5 NS ns0.online.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0