Depends where you trace it all back to. If you see the roots of high-tech (and most of the key references) as being in the early to mid 19th century, then it's British: Decimus Burton and Richard Turner with the great botanical glasshouses, Paxton similarly a bit later, Brunel and Digby Wyatt with stations etc. Eiffel and Chareau are latecomers in this area.
The French equivalent of the Crystal Palace in tech terms would be the Palais des Machines by Ferdinand Dutert at the 1889 Paris Expo. But that was just a wonderful big shed, and came 38 years after Paxton's first Crystal Palace.
Thn again, if you trace high-tech back to Gothic cathedrals (expression and dissolution of pure structure) then it's French again, or possibly Arabic. Damn!
Agreed about Voysey. He could have been our Frank Lloyd Wright, but the Great War destroyed his client base.