Within five months of his move to Paris, the 20-year-old was lining up against Jonny Wilkinson's Toulon in the Top 14 and he gets a chance to stake a claim for a place at this summer's IRB Junior World Championship when title-chasing England face France in Saint Nazaire.
Davies takes over from Gloucester's Jordi Pasqualin on the bench and title-chasing England make three changes to the starting line-up following their 27-6 win over Scotland.
London Irish's Tom Homer - the leading points scorer at the 2009 Junior World Championship - returns at full back.
Shaun Knight (Gloucester Rugby) comes into the front row with Joe Marler (Harlequins) switching to loose head and Will Welch (Newcastle Falcons) steps into the back row with Jamie Gibson (London Irish) moving to Number eight.
England's Under 20s can still claim the U20 RBS 6 Nations title but will need events tonight in Athlone to go their way.
Ireland have a superior points difference and a big win over Scotland may leave captain Jacob Rowan's side with too much to do this weekend.
England Under 20
15 Tom Homer (London Irish)
14 Marcus Watson (London Irish)
13 Andrew Forsyth (Leicester Tigers)
12 Tom Casson (Harlequins)
11 Sam Smith (Harlequins)
10 Rory Clegg (Harlequins)
9 Sam Harrison (Leicester Tigers)
1 Joe Marler (Harlequins)
2 Jamie George (Saracens)
3 Shaun Knight (Gloucester Rugby)
4 Calum Green (Leicester Tigers)
5 Charlie Matthews (Harlequins),
6 Will Welch (Newcastle Falcons)
7 Jacob Rowan (Leeds Carnegie, captain),
8 Jamie Gibson (London Irish)
Replacements
16 Arthur Ellis (London Wasps)
17 Lee Imiolek (Sale Sharks)
18 Danny Wright (Gloucester Rugby)
19 Jackson Wray (Saracens).
20 Charlie Davies (Stade Francais)
21 Mark Atkinson (Sale Sharks)
22 Tom Catterick (Newcastle Falcons)
