Would "dramedy" be a better term? I don't really know how you're even arguing this unless you're nitpicking.
Wikipedia, IMDB, and the movie's own site all refer to it as a comedy, Jaques Tati pretty much exclusively did comedies, and it's obviously playing for laughs, as well as for bittersweet allegory for parenthood. I just feel like the former fell flat and the latter wasn't the kind of thing that could carry the film.
Maybe my expectations are colored by Tati and Chomet's other works, but I don't think it worked as well as either a Chomet or a Tati film, you know?
I also feel like the kind of father-daughter allegory, while poignant, would have worked better with an actual father and daughter and not just some weird girl who can't speak the same language and follows a stranger home like a lost puppy. I think you'll probably figure out if it's for you pretty early in the movie. It's pretty consistently paced. I didn't find it boring, but definitely slow and ambient. YMMV, but you'll know by the time you get an hour in.

