Vanderkindere, from Belgium, sells on 13 December 2017 a "Monogrammed, dated (19)22, Antwerp" geometric collage, estimated at 700 to 900 Euro.
It turns out to be a work by Jozef Peeters (1895-1960), who came into contact with Futurism in 1918 and from 1920 on was one of the earliest and most important abstract painters in Belgium. He was one of the central figures in the thriving art scene in Antwerp in the 1920s, together with poet Paul van Ostaijen and Michel Seuphor, which attracted international names like Kandinsky and architect Le Corbusier (who designed a villa in Antwerp and made plans for the new city on the left bank of the Scheldt). As a work from 1922, this is a very early and rather nice example.
Looking at the prices other works of the period fetch, I guess this should be worth 10,000 Euro instead of the 700 Euro estimate.
UPDATE: sold for 2,800 Euro, still cheap if it's real.