Jules Gimbert’s try 15 minutes from time secured the bonus point for France under-20s and clinched a double celebration in Colwyn Bay as they beat Wales 24-3.
That ensured that both Les Bleuets and France Women had claimed the titles in north Wales on Friday, with the latter also taking the Grand Slam.
The visitors were dominant up front and looked to be well on their way to the five points when they led 17-3 at the break.
But they were made to sweat after defending for much of the second half before Gimbert’s score.
That was enough to see them top the table, ahead of England on points difference, despite their convincing win over Ireland.
France got a dream start when Cai Evans had a kick charged down in the very first minute by hooker Guillaume Marchand. Romain Ntamack was the fastest to react, poking the ball through and dotting down for the first try. He surprisingly missed the conversion but France led 5-0.
Wales responded well, and from their first real period of possession, Evans cut the deficit to two points with a penalty following a maul infringement.
France made a big impression with their first scrum, shunting Wales off their own ball, and that was an indication of the power of the visiting pack.
After turning down a shot at goal, France used their forwards to suck in the Welsh defence before spreading it wide and it was Clément Laporte who sniped over from close range after Pierre-Louis Barassi was stopped just short.
France almost had their third try just before the half-hour when Cameron Woki dotted down after a scrappy lineout but after consultation with the TMO, a knock-on from Daniel Brennan saw the try ruled out.
However it as only a temporary respite as Les Bleuets crossed from close range, with Woki the man to get it. Ntamack converted for the first time and France led 17-3.
France were one try away from the bonus point, and looked set to get it before half-time when they had a five-metre scrum and marched the Welsh back. But after an initial penalty, the home scrum held and they survived through to the break.
While France had dominated much of the first half, the Welsh responded with all the possession and territory for almost 20 minutes to start the second.
They turned down a number of shots at goal in a bid to get a try, but the French defence was able to repel them.
Yet France were still searching for that bonus-point try and with time starting to tick away and England assured of maximum points against Ireland, the title was very much on the line.
But just as it appeared Les Bleuets might let it slip, they produced a breath-taking counter-attack which saw Barassi go clear before finding Gimbert inside him for the try. Ntamack’s conversion made it 24-3.
Wales deserved a try after putting in so much effort in the second period, but Taine Basham was just denied when he picked from a ruck but was held up over the line.
France did end the game with 14 men, with Georges-Henri Colombe sin-binned for a dangerous clearout in a ruck two minutes from time.
But it did little to dampen their celebrations as they claimed the title for the first time since they won the Grand Slam in 2014.