When I lived in Amsterdam, I rode a regular (non-folding) bike. It didn't have gears - but I didn't need them. If you do in-city riding, and your town is planar, gears are not necessary. And you won't be going 45 kph anyway.

On the other hand, if you ride 70 Km a day - why would you even need a _folding_ bike? That means you do serious cross-country riding. Use a regular bike.