Close to 550, although possible, its a rare combo. You would need to have immaculate bilingual skills, atleast a post grad degree and a few years of exp. However, as soon as a person is close to achieving that, his age score drops. Most of them get married etc. So, you have to be standing on that thin golden line in your life which not a lot can do.
furthermore, comming above 500 would be hard for non bilinguals. tons of people atleast in this forum are not very keen on learning french.
And tgere are people, who know a bit of french, but never got tested becoz you could get away with just ielts in the last CEC program.
Hence i believe that anybody above even 480 would be less than 2% of the entire pool.
your thoughts??!!