You don't mention when you're going, and whether or not you can "make it" from Tree Lighting to France in that amount of time depends greatly on when you're there. If it's Christmas week, absolutely impossible. If it's the first week of December ... maybe, but not likely.
The ceremony ends at 6pm, but there is a HUGE audience for that show each night, and getting out of the crush of people won't be easy. Even during the first week of December, when crowds are relatively light, getting from point A to point B in ten minutes will be fairly impossible. Even if your DH leaves early to go sign in at France, it's entirely likely that you could leave the tree lighting at the stroke of six and not show up at France until 20 after, or later.
If you want to see the show, you need to stand in front of the tree, which means that when the show ends, everyone tries to leave from that area at the same time, and it's a HUGE crush of bodies, strollers, bags, backpacks, kids, wheelchairs, and Santa hats. It can take ten minutes just to START moving, particularly during Christmas week. And if you don't stand in front of the stage -- and opt for a spot on the side, nearer the promenade to France -- then you won't really see the show, so it kind of defeats the purpose.
If you MUST schedule your PS at France for 6:10pm, then I would suggest skipping the tree lighting and try seeing it on another night, perhaps a night when you can pop into Epcot just to see the ceremony, and then head back out afterwards.
