Create a socks proxy with SSH, but use a specific interface for outbound traffic

Question

I have a linux server who have an interface "tun0" which is a VPN connection and I want to start a proxy on it for listing eth0 but use tun0 to get internet.

(default route on the server stay on eth0)

eth0 : ip 91.xxx.xx.xx ( public ip ) tun0 : 10.8.8.8 ( VPN )

Connection with tun0 work with a command like :

curl --connect-timeout 2 --interface tun0 http://XXXXXXXX

 ssh -v -C  -N -D *:1081  -o "ExitOnForwardFailure yes" -o "ServerAliveInterval 60"  localhost

Proxy work, but, use eth0 for acces to internet.

I tried to use "Bindaddress", but not success