The comics are invading the auction houses. After several high-priced sales of original comic art (see New World Record: Tintin Comic Tops $3 Million and Tintin Shooting Star Cover Art Sells for $2.9 Million), Sotheby’s and Christie’s will both hold comic art auctions this month in Paris, with works from prominent comic artists including Hergé, Charles Schulz, Jacques Tardi, and Albert Uderzo. According to the AFP, the sales are “expected to bring in millions.”

Sotheby’s Paris will have 288 lots on the block this Saturday as a part of its Bande Dessinée auction. A notable work includes an original 1938 Hergé illustration of Tintin for the French publication Le Petit Vingtième. Tintin made his debut in issue 11 of the children’s supplement in 1929. The work has a pre-sale estimate between €450,000 and €480,000.

“Tintin is part of history,” said Eric Leroy, of Artcurial reports the AFP. “It is becoming very difficult to find good quality drawings by Hergé today.” Artcurial sold a record breaking plate by Hergé for more than $3,000,000  back in May 2014. “His drawings have already disappeared into private collections and won’t come back out again.”

The Sotheby’s auction will also feature original works from several prominent North American comic artists including Winsor McCay, Harvey Kurtzman, Dave Stevens, Will Eisner, Carl Barks, Robert Crumb, and Frank Miller. One notable lot is original comic art from Miller’s New York Times best-selling Batman graphic novel, The Dark Knight Returns with a €22,000 to €25,000 pre-sale estimate.

Sotheby’s Paris held its first comic auction back in 2012, where the top sale went to a Hergé 1941 original comic art from L’Étoile Mystérieuse (The Shooting Star) selling for €234,750 from a low €220,000 pre-sale estimate. Out of 89 lots for auction, 27 lots sold. This will be the second comic auction held at Sotheby’s Paris.

The Christie’s auction set for March 14 will feature over 400 lots, with 10 Tintin original works for sale. A large ink drawing featuring Tintin carrying books will have a high pre-sale estimate of €700,000. The illustration was originally designed for a poster advertising a French bookseller.