Apex domains cannot have CNAME records.
Question and response
Question
dig 128-26.80.210.62.in-addr.arpa. NS
Answer
128-26.80.210.62.in-addr.arpa. 5 NS ns0.mcra.fr.
128-26.80.210.62.in-addr.arpa. 5 NS ns3.mcra.fr.
128-26.80.210.62.in-addr.arpa. 5 NS ns2.mcra.fr.
128-26.80.210.62.in-addr.arpa. 5 NS ns1.mcra.fr.
Authority
The response has no authority records.
Additional
ns0.mcra.fr. 5 A 62.210.80.154
ns1.mcra.fr. 5 A 62.210.80.131
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0