Nuremberg's mayor Ulrich Maly has condemned the upcoming sale as being “in bad taste,” speaking to Süddeutsche Zeitung newspaper.
Among the items to go under the hammer are a mountain lake view with a starting price of 45,000 euros ($51,000) and a wicker armchair with a swastika symbol presumed to have belonged to the late Nazi dictator.
The Weidler auction house is holding the “special sale” in Nuremberg, the city in which Nazi war criminals were tried in 1945.
The auction made headlines days before its start after several artworks were withdrawn on Thursday on suspicion they were fakes and prosecutors stepped in.
Sales of alleged artworks by Hitler — who for a time tried to make a living as an artist in his native Austria — regularly spark outrage that collectors are willing to pay high prices for art linked to the country's Nazi past.
“There's a long tradition of this trade in devotional objects linked to Nazism,” Stephan Klingen of the Central Institute for Art History in Munich told AFP.
“Every time there's a media buzz about it… and the prices they're bringing in have been rising constantly. Personally, that's something that quite annoys me.”
In Germany, public displays of Nazi symbols are illegal but exceptions can be made, in educational or historic contexts for instance. To comply with the law, the auction house pixellated the swastikas on the wicker chair and a blue-and-white Meissen porcelain vase in catalogue photos, and has covered them up on-site.
But none of the paintings include any of the totalitarian party's insignias.
According to Klingen, Hitler had the style of “a moderately ambitious amateur” but his creations did not stand out from “hundreds of thousands” of comparable works from the period — making their authenticity especially hard to verify.
A haul of 26 pieces originally featured in the catalogue have been removed from sale after suspicions were raised that they might be fakes.
The watercolours, drawings and paintings bearing “Hitler” signatures featured views of Vienna or Nuremberg, female nudes and still lifes, the auction house said. They were offered by 23 different owners.
Prosecutors on Wednesday collected 63 artworks from the Weidler premises bearing the signature “A.H.” or “A. Hitler”, including some not slated to go under the hammer Saturday.
The Nuremberg-Fuerth prosecutor's office said it had opened an investigation against persons unknown “on suspicion of falsifying documents and attempted fraud”, chief prosecutor Antje Gabriels-Gorsolke told AFP.
“If they turn out to be fakes, we will then try to determine who knew what in the chain of ownership,” she said.
Weidler said in a statement that the paintings' withdrawal from sale “does not automatically mean they are fakes”.