Yes, since 1934 when the Dutch language was overhauled it would have been: Koopt bij de_ middenstand. When I grew up and while my father was a blue collar worker (Housepainter) we detested the "middenstand-- the persons who owned the stores-- as they would not even talk to us!

Middenstand was the medium social status; manufacturers and large factory owners were the "rich" then the midden =(middle) stand and then the rest of the world. Hopefully things have changed in the last few years. Jopie