What is the difference between layer 2 vpn and layer 3 vpn?

All what layer 2 VPN decisions based on mac address that is tunneled to from a building to a building and as far as Layer 3 VPN  decisions based on IP addresses from one subnet to many other different subnets

With My limited Knowledge  , At first Layer2 vpn was referred to Frame Relay & Layer3 VPN to best effort IP-VPNs, now both the VPNs delivered from an MPLS network  to meet High Flexibility ,granular Scalar Bandwidth.

L2 VPN customer sites appear to be on same LAN even if sites are geographically dispersed whereas L3 VPN networks allow multiple customer sites to communicate securely at the IP level over a provider managed MPLS network. L3 VPN is connected to one or more provider routers and each associated provider router maintain a separate IP forwarding table for each VPN known as virtual forwarding table (VRF).