I have bags in both leathers and here are some differences I have noticed. (My Clemence is an Evelyne and Togo is a Birkin).
Clemence is a thicker leather.
The grains on Clemence are flatter. On Togo if you rub your hand over the bag it is not necessarily soft but on Clemence it is. I think of Clemence as buttery ... I feel that it seems slightly more luxurious than Togo, even though I totally love, love, love my VA Togo B.
I have found Clemence to have a light sheen whereas not so with Togo.
Togo can have veining from a little to a lot but I don't believe there is any veining in Clemence.
Some say that Clemence is heavier but most say only a teeny bit. I tried an empty Clemence 35 Birkin and it didn't seem heavier than my Togo to me. My next Birkin will be Clemence.
Clemence is slouchier. If you look at the bag from the side, on Clemence you can see less structure. Even though my Togo is slouchy, it still looks nothing like Clemence.