Updated

A red notebook of 33 pencil drawings by Pablo Picasso stolen from the Paris museum bearing his name will be hard for thieves to sell, France's culture minister said Wednesday.

The theft was discovered Tuesday morning by an employee of the Picasso Museum. The notebook had been kept in a second-floor glass display case that can only be opened with a special instrument.

"It's difficult to sell, a notebook of pencil sketches made in the 1920s," Culture Minister Christine Albanel said. "Even the Picasso family said it has a scientific value" — unlike a painting.

"It seems bizarre, to say the least," she added.

About 1,000 people a day visit the museum. The culture minister said four security personnel make rounds in six exhibition rooms. Albanel could not provide an exact time of the break-in.

The stolen sketchbook, shiny red with the word "Album" inscribed in gold on the front, dated from 1917 to 1924, according to a Culture Ministry statement. It measured 6.3 inches by 9.5 inches.

The Picasso Museum, in Paris' old Marais neighborhood, is dedicated to the Spanish-born painter, a founder of the Cubist movement and leading 20th-century artist.

Museum head Anne Baldassari said she didn't think it was a commissioned theft — one specifically ordered up by an unscrupulous collector — but added the museum was "waiting to hear from the investigation."

She would not speculate about the notebook's value, which a police official said earlier was likely worth $11 million.

"This is the type of object you don't find in private collections but in museums," Baldassari said.

Robert Korzinek, an art expert at specialist art insurer Hiscox, agreed that selling the notebook would be difficult.

"This theft looks ill conceived and opportunistic. The likelihood of being able to sell this type of work and achieve a financial return is extremely low," he said.

Francis Briest, co-president of Artcurial, a Paris auction house, told Associated Press Television News: "If we were shown a little red book tomorrow, well, I think we would all go straight to the police."

In August 2007, French investigators recovered two Picasso paintings and a drawing worth more than $66 million stolen from the artist's granddaughter's home six months earlier. Two of three suspects arrested were carrying the rolled-up canvases as police closed in.

Police had been tipped off by an art dealer after the theft at the luxury Paris apartment of Diana Widmaier-Picasso and suspected the thieves were looking to sell their loot.