Head coach Chris Horsman has made 14 changes to the team which beat England on Tuesday, three of which are positional: Harri Doel (wing to fullback), Osian Knott (outside to inside centre), and Oliver White (blindside to openside).
Teddy Williams, who continues in the second row, becomes the only player to have started every game of the series.
Rob Brookson is back at number six and captains the team, having led the side in Wales' opening match against hosts South Africa Schools. Fly-half Evan Lloyd makes his first start of the series.
"France are a fantastic side, but we don't dwell too much on the opposition," said Horsman. "That's not us being arrogant, it's about our players and the U18 pathway. The outcome of Tuesday's match was us beating England, but the most important thing was the process of doing that.
"So while France tomorrow is going to be a huge opportunity for us, it's not about beating France: it's about this group of players understanding how you go about beating a team like France."
Wales U18 team to face France: 15 Harri Doel (Coleg Sir Gar/Scarlets), 14 Ewan Rosser (Coleg Gwent/Dragons), 13 Joe Roberts (Coleg Sir Gar/Scarlets), 12 Osian Knott (Coleg Sir Gar/Scarlets), 11 Morgan Richards (Newport High/Dragons), 10 Evan Lloyd (Coleg Gwent/Dragons), 9 Dan Babos (Dragons Academy/Dragons), 1 Garyn Phillips (Colege Gwent/Dragons), 2 Llew Phillips-Taylor (Coleg Sir Gar/Scarlets) , 3 Archie Griffin (Marlborough/Bath/Exiles), 4 Morgan French (Bromsgrove/Worcester/Exiles), 5 Teddy Williams (Glantaf/Cardiff Blues), 6 Rob Brookson (c) (Coleg Gwent/Dragons), 7 Oliver White (Llandovery College), 8 Ioan Davies (Coleg y Cymoedd/Cardiff Blues)
Replacements: 16 Cameron Lewis (Coleg Sir Gar/Ospreys), 17 Luke Yendle (Newport High/Dragons), 18 Ben Warren (Coleg y Cymoedd/Cardiff Blues), 19 Callum Williams (Maes y Gwendraeth/Scarlets), 20 Jac Morgan (Coleg Sir Gar/Scarlets)
21 Jac Price (Coleg Sir Gar/Scarlets), 22 Carwyn Tuipulotu (Sedburgh/Scarlets), 23 Ellis Bevan (Bryanston/Exiles), 24 Sam Costelow (Oakham/Leicester Tigers/Exiles), 25 Ioan Lloyd (Clifton/Bristol/Exiles), 26 Louis Rees-Zammit (Hartpury/Gloucester/Exiles), 27 Aneurin Owen (Ysgol Gwynllyw/Dragons)