Résumé : Pieter Brueghel the Younger (c. 1564/65 – 1637/38) is a well-known painter who reproduced the works of his celebrated father Pieter Bruegel the Elder (c. 1525/30-1569). We collected the sales of his original works as well as those from his atelier and followers over the period 1972-2015 and compare the prices of two categories of works: his autograph works, and all others, whether partly autograph or untouched by him. Confusion among the types was floating around, since the same compositions exist in many versions and dimensions, and were probably even executed by different painters. In 1997-1998, the German independent art historian Klaus Ertz curated a large itinerant exhibition in four European countries dedicated to Pieter the Younger. At the time, it was known that he was working on a catalogue raisonné (CR) of the painter to which he referred substantially, though it came out in 2000 only. We use difference-in-differences estimation to establish that the exhibitions and the information concerning the catalogue had a significant effect on the prices of autograph works. Though we cannot judge whether Ertz’s attributions are right or not, it seems that buyers started feeling more confident, since they were ready to pay roughly 60 percent more for works considered autograph after the late 1990s.