I picked it up in England, which is where I'm originally from (dus mijn vlaams is niet zo goed!). Unfortunately I paid a lot more than you did
I tried a little OA on the rusty painted areas, but it didn't do much. In the end, I just gave all the paint a good clean and polish, but the rust is all still there. The OA worked really well on the chrome parts (wheels, handlebars, levers, etc.). I bought a children's pool from Brico and added 1 dessert-spoon (what Americans call a table-spoon) of OA per 4 litres of water. Then I left the parts in the solution for around 3 hours (or overnight for the really rusty bits). Then I neutralised the parts by washing them in water with bicarbonate powder in it (very cheap from the baking section in Delhaize).