I moved the filament spool on the top of my printer. I searched for a decent filament guide and I printed 2 or 3 models until realizing that I have more chances to succeed if I design it myself.
I used the following parts :
1 x M3 x 20 mm Screw to tighten the ball bearing
1 x 608 ball bearing
1 x M3 x 10 mm Screw
1 x M3 Nut