The two wingers are already certainties for Stuart Lancaster's final squad and of those hoping to join them, Henry Slade took the honours ahead of fellow debutant Sam Burgess in what is likely to be a head-to-head battle for one remaining centre berth.
Rugby league convert Burgess showed plenty of trademark big tackles and some deft handling but blotted his copybook when he was yellow-carded for interfering at a tap-penalty, exposing the lack of union experience that might make him just too much of a World Cup risk only months after his switch.
Slade, on the other hand, delivered an assured, high-quality display of creative play that will have impressed the coaching staff.
Callum Clark was another who spoiled his debut with a yellow card. Already fighting to shake off a reputation for ill-discipline, the flanker looked distraught when he trudged off after being sin-binned for a dangerous clear-out at a ruck knowing his tournament chances had probably gone.
The match was the first of the new season for both teams and also a dry run for World Cup organisers, with an 8pm local time kick off and local road closures emulating what will be the tournament opener when England play Fiji on Sept. 18.
England went into the game with three uncapped starters and another on the bench while France coach Philippe Saint Andre, already a renowned shuffler, was in similarly experimental mode with a team containing only five men who started at Twickenham in the Six Nations in March.
Watson scored the opening try after 10 minutes with a quick-footed shuffle to create space where there was seemingly none but his second seven minutes later was the result of some sparkling interplay by Slade, Burgess and May.
France, wearing unfamiliar red shirts, struggled to make much headway but three penalties by Morgan Parra kept them in the game as they turned round 12-9 down.
While Burgess was watching from the bin early in the second half, Slade made the most of his moment in the limelight with a classy flicked pass as England scored their third try when May collected a neat kick by fullback Alex Goode.
After the usual wholesale changes, France took control of the scrum and their pack drove Fulgence Ouedraogo over for their only try after an hour but it was a rare moment of progress against an impressive England defence.
It was the 100th meeting between the cross-channel rivals, and the 101st will take place in Paris next Saturday when wholesale changes are expected on both sides.
