So my grandma used charbon (coke) when she was a kid. And my mom uses charbon (charcoal) for her barbecue.
In journals and scientific papers the words coke will be used.
In everyday speech, coke means cocaine. Coca is short form for coca cola. And cola is the generic for a coca cola flavored soda.
I admittedly used a very rare/specialist example homonym. What I'm really wondering is how context plays into it. If you're ordering drinks in France and an English speaker says they'll have a Coke, does anyone really think they are referring to cocaine? Coke is vernacular slang for cocaine in American English too, but no one confuses this with usage of the brand name to refer to soft drinks (specifically Coca-Cola, or to soft drinks in general, which is a regional thing).
That's also called "coke", which is why there's a Tintin book called "Coke en Stock". [0]
That said, if you say "coke" in English, almost nobody will think of fuel, and the same is true for French speakers today.
[0] https://www.amazon.com/Aventures-Tintin-Stock-French-Sharks/...
There's a button saying "58 languages" on the trailing edge of where the title of the page is. It opens a drop-down with language selection.
(Presumably the UI is different on mobile, speaking about web.)
