I first saw them in Paris as well. They are everywhere and Parisian's ride in every sort of weather. I just ordered one from Urbanrider.co.uk for $99 US plus $17 shipping. Anyway, I hope to extend my riding period a month or two on both ends. January and February will still be off limits but I think I can start spring riding a little sooner and ride into early winter in relative comfort. I'll let everyone know how it works out.In Paris, France I observed scooter riders using an “Apron” or I’d call a lap blanket .
It wasn’t really that cold either.
They are very common in North European cities (not U.K. where they are considered too girly, but starting to be used more). Very warm indeed on bikes with heat bents in the tunnel.
As well as warmth, they keep rain off the everyday/work clothes so lots of people leave them on year round. Also a bit of aerodynamic advantage but I don’t think anybody uses them for that apart from a handful of hypermilers.