irb(main):001:0>  name = "réunion-journalière"
=> "r\303\251union-journali\303\250re"
irb(main):002:0> File.open(name, 'w'){|f| f.write 'x' }
=> 1
irb(main):003:0> exit

$ ls -al
> total 36
> drwxr-xr-x  2 rlivsey rlivsey 4096 Jul  3 22:00 .
> drwxrwxr-x 10 rlivsey rlivsey 4096 Jul  3 12:20 ..
> -rw-r--r--  1 rlivsey rlivsey    4 Jul  3 21:53 r??union-journali??re