"Here's looking at you, kid" in French

I haven't seen the dubbed version but I once saw it with French subtitles and I think he just said "sante" or "A votre sante". With appropriate accents in the subtitles of course.

I do remember that the last line, "Louis, I think this could be the beginning of a beautiful friendship" became "Maintenant, nous sommes amis!"

Disappointing.

Then there was the Western where the tough cowboy bellies up to the bar and says, "Gimme a shot o' red-eye." Subtitle, en français, "Un Dubonnet, s'il vous plait." Cue hysterical laughter from Americans in Paris.

Every time I see or hear "Rayos!" for words I can't put here, I think Spanish translators must be working with an 1830s or older dictionary.
What to do with phrases that defy translation? I'd go with a non verbal "look" or "gesture".

what 1 says is interesting in that i have experienced the contrary -a couple of films i watched not long ago where the french dubbing was more elaborate than the english orignial!

livencabo, you can't replace speech with a gesture or something non-verbal when you are dubbing a movie. It's bad enough when the lips are not synchronized with the words, but if the lips are moving and there is no sound, then that's really awful.

Actually, I saw Casablanca on a DVD a couple of months ago, with French subtitles, but don't remember what the phrase was translated as. When I watch a subtitled film in a language I understand, I only occasionally glance at the subtitles to see how accurate they are.

Thinking about some more, my first response refers to the first time he says "Here's looking at you, kid" (in the Paris flashback?). When he says it towards the end (at the airport?) it gets a completely different translation, as it must since there it means something like farewell/adieu. I don't remember how it's translated in that last occurrence, but I do remember noticing that the thread linking the scenes was broken.

Casablanca, one of the best movies of all time....I've consulted German Wikipedia and it offers some interesting bits of trivia. Apparently, the US magazine The Hollywood Reporter wrongly announced that Ronald Reagan would play the male lead in the movie.
Anyway, de.wiki also says that the famous line "Here's looking at you kid" was extemporized by Humphrey Bogart. The original line in the script was supposed to be "Here's good luck to you." The German subtitles translate it as "Ich schau' Dir in die Augen, Kleines. - I'm looking in your eyes, kid."

Here's a link to a French discussion on this topic.

If I remember correctly the phrase is a toast, usually shared with a friend over drinks. It doesn't have an exact meaning even in English. It comes close to "hoping all goes well with you, my dear". I would say "Que te vaya bien, chavita", in Spanish. Something like "Je te souhaite bonne chance, cherie" in French.
I really think that dubbing along with coloring black and white classics is not a good idea. If forced to dub a phrase that was not translatable, I would edit the visual in such a way to cut the voice part.
Bad sync is just bad work.