Bateau-mouche sur la Seine was created in 1896.

mouche is fly and bateau is cake, so ''cake fly'' or perhaps fly on the cake!

I must offer a correction: Bateau in French is boat. Perhaps you were thinking of gateau, which is a kind of fruit cake. Mouche does not simply mean 'fly', that is but one possible meaning of the word as used in the phrase "Bateau Mouche". A mouche is also a specific type of boat.

Le Bateau-Mouche

The term is a "bateau mouche".

they are open excursion boats in Paris that provide visitors with a view of the city from the river Seine