Hardwick and Heyes are in their second season in the Six Nations Under-20s Championship and both were involved in the opening round against Ireland last weekend.
England head coach Steve Bates makes three changes to the side that lost to Ireland with Cameron Redpath at inside centre in place of Hardwick, with Ollie Lawrence at outside centre and Arron Reed selected for his debut on the wing.
Bates said: “There was a lot of disappointment at the start of the week off the back of Friday’s result but we’ve trained really well and the players are looking forward to getting out there on Saturday.
“We know we didn’t look after the ball well enough last week, played from too deep and lacked a bit of organisation which you would expect from a new group at this stage in the tournament. We’ve had a good preparation and want to go out and continue to play high-tempo, high-intensity rugby but get the balance right.
“We’re hoping for a large crowd and we have to get them on our side by playing some good rugby but controlling the game a little bit more.”
There is live coverage of Saturday’s game from Sandy Park, Exeter on Sky Sports.
England U20s (v France, Saturday 12.05pm)
15 Josh Hodge (Newcastle Falcons)
14 Ollie Sleightholme (Northampton Saints)
13 Ollie Lawrence (Worcester Warriors)
12 Cameron Redpath (Sale Sharks)
11 Arron Reed (Sale Sharks)
10 Marcus Smith (Harlequins)
9 Sam Maunder (Exeter Chiefs)
1 Olly Adkins (Gloucester)
2 Nic Dolly (Sale Sharks)
3 Marcus Street (Exeter Chiefs)
4 Joel Kpoku (Saracens)
5 Alex Coles (Northampton Saints)
6 Ted Hill (Worcester Warriors)
7 Aaron Hinkley (Gloucester)
8 Tom Willis (Wasps)
16 Ben Atkins (London Irish)
17 Kai Owen (Worcester Warriors)
18 Joe Heyes (Leicester Tigers)
19 James Scott (Worcester Warriors)
20 Rusiate Tuima (Exeter Chiefs)
21 Ollie Fox (Yorkshire Carnegie)
22 Tom Hardwick (Leicester Tigers)
23 Tom de Glanville (Bath Rugby)
Tigers prop Sam Grahamslaw retains his place in the Scotland front row as they host Ireland in the second round of the Under-20s Six Nations on Friday evening.
The Scots make three changes following defeat by Italy last weekend with Rufus McLean named at full-back, Ewan Ashman replacing the injured Finlay Scott at hooker and Cameron Henderson in the second row.
Skipper Tommy Reffell misses out due to injury as Wales face Italy at the Stadio Danilo Martelli in Mantova on Sunday. Tigers club colleague Sam Costelow retains his place among the replacements.