I love the question and its hint "How would you say ''I haven't been in France for long.'' ?(literally: I haven't long arrived to France.)
The answer: Je ne suis pas arrivé en France depuis longtemps.
Je ne me sens pas intelligent et j'ai l'air stupide comme ça depuis longtemps !!! I think i get it! I know I got it! OOOPS me no get it!!
The hint imposes a thought process on the reader which would not be there otherwise. Clever... it reinforces the understanding of the verb 'arriver' as a sort of process.... and shakes up the marbles in the old nuggin.
However!!! My question. I arrived in France 'yesterday' and I am telling someone today that "I haven't been in France for long". I am thinking it calls for the Present indicative and depuis. Since i was in France as of yesterday(the past) and am still here today (the present).
Je ne suis pas en France depuis longtemps!!!
Without the hint and its imposition of the verb 'arriver' then doesn't this question change dramatically.
Help!!!!!!!