France were first on the scoreboard with a penalty for Toulouse full back Thomas Ramos, but Wales then scored three unanswered tries, a brace for full back Steffan Evans with captain and right wing Dafydd Howells also touching down.
The Welsh youngsters displayed good decision-making, angles of running and skill levels for all three scores, and although Ramos notched another penalty, the hosts went in 19-6 to the good at the break.
Half backs Dan Brooks and Angus O'Brien controlled the game well, O'Brien also slotting two conversions.
The Dragons and Caerleon pivot added a penalty early in the second half but Wales then dropped their guard somewhat and allowed the visitors back into the game. France scored two tries from outside half Lucas Chouvet and replacement No 8 Matthieu Majeau, Ramos adding the extras to take France within two points of Wales at 20-22 and putting Wales under considerable pressure.
However, Wales responded well with some fifteen man rugby, No 8 Tom Phillips and lock Josh Helps amongst those to make the hard yards before the backs showed some lovely handling skills to send Howells over, O'Brien's conversion sealing the win.
France had the last word with a try for Thomas Fortunel in the dying moments, converted by Ramos but Wales had done enough.
Wales play England next, at St Helens on Sunday 10 March (2.30pm).