i didnt know the answer, i found it in between my post and your answer, but i still have an issue the defautl ACL is applied on the folders and not the files.
I did : setfacl -dm o::5 folder/
drwx---r-x+ 2 root root 4096 Apr 20 13:19 dir => OK
-rw----r-- 1 root root 0 Apr 20 13:19 file =>...