Earning his 13th cap, midfielder Tom wore the captain's armband and played 90 minutes as Harry fired the Young Lions into a 2-0 lead inside 23 minutes at a rainy Stade Francis-Le Ble in Brest.
Harry took his first goal clinically after racing onto Tom Ince's pass and clipping the ball over the advancing Alphonse Areola in the 20th minute.
It was 2-0 within three minutes and 'Pritch', starting for the first time and earning his third cap for the Under-21s, played a key role.
He spun away from Americ Laporte on the right touchline and passed inside for Ince who darted into the box and fired across goal from the right angle with Harry on hand to tap home.
That made it eight goals in 10 caps for the in-form striker, who has scored 10 goals for us in all competitions and now 14 for club and country this term.
France hit back through Yaya Sonogo's double to level before half-time, Alex was substituted at half-time, Harry was substituted on 65 minutes and France won it when Kingsley Coman fired home in the 73rd minute.
Elsewhere, defender Dominic Ball played 90 minutes as England Under-20s drew 1-1 with Portugal before winning a penalty shoot-out 4-3 at the Estadio Sergio Conceica, Coimbra.
Josh Onomah played for 83 minutes as England Under-18s toppled Poland 4-1 in a friendly in Gdansk. Kyle Walker-Peters came on in the 72nd minute.
Kenny McEvoy played the full 90 minutes as the Republic of Ireland drew 2-2 in a friendly against Russia in Marbella.
Christian Eriksen and Vlad Chiriches are set to meet in friendly action as Denmark travel to Romania on Tuesday.
There are also some high-profile friendlies with Erik Lamela and Federico Fazio part of the Argentina squad taking on Portugal and Cristiano Ronaldo at Old Trafford.
Hugo Lloris' France squad face Sweden at home.