Thank you for your help, I tried to add configuration in bold in my interface but I can't ping the peer IP (10.10.10.2). I learn a mac from the cloud peering but it's stored in vlan 1 inside router"s cam.
I captured traffic using the monitor capture feature on Cata 4500-X I saw arp request from cloud services with the correct tag information in the packet (3000 for S-vlan and 100 for Cust vlan).
When I did a ping I saw an arp request sent by the router but I can't verify tag information because monitor feature operate before encapsulation.
have you already deploy this kind of feature (selective QinQ ) ?