Jon Searles' photos with the keyword: LGV SNCF France

Here it's easier to tell we're in France. The large number of tracks is the giveaway, as well as the land even flatter than Belgium. Other than on the Shinkansen system, there aren't any other networks that I can think of as well suited to highballing as the post-1990 SNCF LGV system.

The Eurostar doesn't really pick up speed until it's well out of Brussels, although I don't know off hand if this was before or after crossing into France and taking the CTRL at Lille. I've just said "France," for the sake of convenience. The Eurostar is, at least, a French train. That we were at full cruising speed was and is, however, obvious.