Mohn, listed at 261 in the Forbes' 2009 billionaire list with a net worth of $2.5 billion (€1.7), was a Bertelsmann executive for over 60 years, leaving a firm that now employs more than 100,000 people in over 50 different countries.
"Bertelsmann mourns the loss of one of the greatest entrepreneurs of our age," the current chairman and chief executive officer, Hartmut Ostrowski, said in a statement.
"All of us at Bertelsmann, the entire nation, as well as our friends in Europe and the rest of the world have lost an entrepreneur and benefactor par excellence," he added.
Mohn died on Saturday after a long battle with illness.
The company he leaves behind is facing serious problems, hammered by falling advertising revenue and the global economic crisis.
Ostrowski is currently overseeing the biggest cost-cutting operation of its history.
In May, the group reported a loss in the first three months of the year of
€78 million compared to a net profit of €35 million in the same period last year.
Among the interests Bertelsmann controls are the RTL and M6 television channels and magazine titles such as Gala and Geo. It also publishes books.