BRUSSELS — Companies like Google that digitize artworks and books from public bodies should allow other companies and institutions to commercialize those materials after seven years, three experts advising the European Commission said Monday.

The experts, including Maurice C. Lévy, the chairman and chief executive of Publicis, a communications and advertising company based in Paris, also encouraged the emergence of additional innovative companies besides Google to help digitize Europe’s cultural heritage.

“We believe there is a lot of opportunity for new players to come and confront Google,” Mr. Lévy said. Google had been “essential in the process” of digitizing cultural materials like books, films, photographs and paintings, but it was not “very good for competition to have one player on the ground,” he said.

The amount of effort needed to digitize Europe’s heritage should generate work for a lot of entrepreneurs, he said.