On paper, out of context (player vs player), I think France are comfortably the stronger side; however, both are considerably less than the sum of their parts. England, frankly, because of Southgate. France, I don't know if I'd call it a lack of leadership (although, maybe it's a bit that too), but there's an arrogance and lack of discipline. It cost them against Denmark in Euros. And it probably should've cost them against Denmark in the group stage as well. It's a team full of superstars that acts like a team full of superstars. There's no "glue guy," no one running through walls to help the other guy out. If they win, it's strictly on talent and execution. I'd say Spain and Belgium have a similar "feel." I don't question the individual commitment, but their team dynamics are lacking.
That said, based on current rosters and what both sides have shown, I'd take France 6 out of 10. If Southgate changes how the midfield operates (i.e., Rice isn't isolated and hiding) and Walker is closer to fit than he looked against Senegal, then it's closer to 5-5, might even give England a slight advantage.