Topo = Mouse
I guess it comes from "topographie", a sort of map.
Perhaps this is a connection to comics too.
i think the french just know the italian word. i think there have been other celebrity topi, like Topo Gigio. i wrote a little script tool to explore/confirm my network topology, and i call it gigio :) it's based on testing ad hoc knowledge of my network topology so it's not generally useful.
On a similar note, the "cerf" (deer) in "un cerf-volant" (a kite toy) probably derive from occitan sèrp (snake) as a reference to dragon-shaped kites from Asia.