Things like police checks and the like need to have a certified translation if they're issued in another language, but standard documents such as passports don't need to be translated since they all (or at least most?) are written both in the native language as well as English and/or French. I've never seen a passport that didn't at least include one international language as well.
Likewise, a lot of countries offer the so called international birth certificates that also don't need to be translated since they're already issued in multiple languages, including English and French.
But of course, if this is not the case, then you do have to have it officially translated and certified. It's just usually not the case.
For everything else, all the different kinds of relationship proof that can include different kind of printouts related to banks, utilities, insurance policies, etc - it can all just be a plain copy.