Dear NAGISWAREN2.
Nowadays I'm working with MetroEthernet Virtual Circuit Based, it means we've a MPLS Network and Virtual Circuits carrying services (l2vpn). So, we've just one customer using VPLS and running OSPF over the WAN using a /24 subnet. As the WAN it's L3, physically every connection needs to pass over the PE to reach another one.
Regarding your doubt, I don't know what is the vendor and have no details about your infra or if you're using vlan over the Metro, but in the first look I believe the traffic flow over the PE's to reach another one, but with more details I could be more effective in your answer.
Thank you,