The clash at Outeniqua Park Stadium in George, South Africa kicks-off at 2.00pm (BST) and Northampton Saints centre Tom Stephenson will captain the side.
England narrowly beat France 18-16 earlier in the season in Fylde thanks to tries from wing Anthony Watson and scrum half Callum Braley, but Fletcher knows that this game will be different.
"They're a big, strong side but we have something to gauge ourselves on now and we're looking forward to the challenge," he said.
"We did well to get the win against them earlier in the season, but that was a few months back, this is a different match up in a different environment, but one we're looking forward to."
England Under 18 starting XV against France
15 Howard Packman (Moulton College) (Northampton Saints)
14 Zach Kibirige (Yarm School) (Newcastle Falcons)
13 Nick Tompkins (Oaklands College) (Saracens)
12 Tom Stephenson (Moulton College) (Northampton Saints) (C)
11 Joshua Watkins (Bromsgrove School) (Worcester Warriors)
10 Sam Olver (Oundle School) (Northampton Saints)
9 Ollie Claxton (Adams Grammar School) (Unattached)
1 Alex Lundberg (Hampton) (London Wasps)
2 Sam James (Bishops Stortford) (Saracens)
3 Biyi Alo (Haileybury College) (Saracens)
4 Jake Oldaker (Wellington College) (Bath Rugby)
5 David Hughes (Twyford C&E High School) (London Wasps)
6 Maro Itoje (Harrow School) (Saracens)
7 Steve Uren (Filton College) (Bristol Rugby)
8 Joel Conlon (Ivybridge Community College) (Exeter Chiefs)
16 Gus Jones (Eton College) (London Wasps)
17 Harry Thacker (Leicester Grammar) (Leicester Tigers)
18 Charlie Ewels (Bryanston School) (Bath Rugby)
19 Danny Hobbs-Awoyemi (Moulton College) (Northampton Saints)
20 Callum Braley (Hartpury College) (Bristol Rugby)
21 Nick Carpenter (Filton College) (Bristol Rugby)
22 Billy Burns (Hartpury College) (Gloucester Rugby)