Yes but collecting in both champagne and bordeuax means you lack the cumulative bonus from Bourdeaux trade moving to champagne, as well as the trsde efficiency malus
Right. However you will earn more money in Bourdeaux, Paris and The Channel than you will lose in Genoa.
Op has a stranglehold on genoa, so it makes sense to assume he has more than 50%
You will also lose a lot of trade value, both for the trade power you don't control in Genoa and the percentage of trade value that goes to The Channel (where you wouldn't be collecting).
Paris (champagne) is the default home node, so will always collect there until moved
He said "I made that my trade city and push all my trade there" so I assume his trade capital is in Genoa node and he's not collecting at Paris (Champagne)
Niet, like collecting in ivory coast and sevilla as Portugal
Trying what I said has nothing to do with Portugal.