Did you just make up that 2.0.0.x address or are you a person in France who was assigned that address my the owner? For local experiments you should use one of the three non-routing address ranges: "192.168.x.x" or "10.x.x.x", or "172.16.x.x through 172.31.x.x"
The problem may be that you are using the same address range (2.0.0 x) on both physical interfaces (ethernet and USB). I think it will work if you use the ethernet port and an ethernet switch or hub to connect the two Arduinos.
It may also work if you use separate address spaces on the two interfaces:
Ethernet: 192.168.1.x, Subnet mask: 255.255.255.0
USB Ethernet: 192.168.2.x, Subnet mask: 255.255.255.0