Winger Rhys Williams became Wales' all-time leading tryscorer after touching down twice but France were the victors at the Racecourse Ground in Wrexham.
Williams, 22, who is currently on loan from Warrington to Castleford, touched down on the stroke of half-time for his 12th international try to equal the previous record held by coach Iestyn Harris and grabbed a second on the hour to break it.
Williams' eye-catching efforts were among a host of pleasing aspects for Harris, as his inexperienced side made France fight all the way for the spoils in their first mid-season international for 11 years.
The Welsh had six youngsters on debut in the absence of five regulars through injury, in addition to their Australia-based players, whereas the French were able to call on six regulars from Catalan Dragons.
Led by captain Jordan James on his 25th appearance, the Welsh enjoyed a promising opening but the danger signs were there when scrum-half William Barthau wriggled over the line only for referee James Child to disallow the try for a knock-on.
The opening score came right out of a Catalan training-ground move, with full-back Cyril Stacul taking Bosc's inside pass to glide over for the first of his two tries on 15 minutes.
Bosc added the goal and the visitors dominated the rest of the first half without being able to fully make their pressure count.
Second rower Antoni Maria was held up on his back over the line and winger Jeremy Guiraud was brought back for a forward pass before loose forward Gregory Mounis took Barthau's defence-splitting pass and wrong-footed full-back David James to score his side's second try eight minutes before the interval.
Wales grabbed a foothold in the game on the stroke of half-time when they worked the ball out to the left and Williams took James' pass to go over for his first try.
That buoyed the home side, who made an impressive start to the second half but second rower Andy Bracek's clean break petered out and centre Christian Roets was ruled offside when he touched down Danny Jones' kick to the line.
France re-asserted their dominance when prop Mathieu Griffi burst through for two tries in seven minutes, the second after a superb break by his fellow front rower Mickael Simon.
In between Griffi's double the impressive James scythed through the visitors defence for a deserved try and then combined with Roets to get Williams over for his record-breaking score.
Jones converted both second-half tries to make it 22-16 but the French made sure of the victory when skipper Oliver Elima broke clear and Bosc sent Stacul over for his second try of the match and Bosc kicked his fourth goal.
