Juergen Boos, director of the Frankfurt Book Fair, urged the need to maintain diversity in what people read and publish, adding that Amazon, Apple and Google were "logistics magicians but are not publishers".
"There's no passion there," he told reporters, ahead of the fair's official inauguration later Tuesday before it opens its doors Wednesday.
He warned that to maintain diversity, technical standards, such as payment systems that influence the way people read and access content, should be designed to serve customers.
"Technical standards are tools. They must be designed to serve people and their needs, not the other way around."
He said companies such as Apple and Amazon were "machines for customer retention".
But he stressed that international publishing was not "paralysed with fear" and was fighting back with innovations, while smaller, independent book shops are also developing new ways to entice customers.
Asked about a bill approved by French lawmakers last week to prevent Amazon from offering free deliveries of discounted books, Boos said: "We look at France actually in many matters as an example."
He said he did not know whether going as far as making new laws was the answer but that France's support for its independent book trade through tax relief, for example, showed an "esteem" for a branch that is part of the country's culture and not just commercial.
"I think there we can actually learn from France."
Despite the pressure from the US giants, publishers were upbeat about the industry's future as it adapts to embrace the digital age.
"The much heralded digital revolution is no longer on the way, it has arrived," Stephen Smith, chief executive of US-based Wiley publishing company, told reporters.
"It's here, and it is now, and it is causing publishing leaders around the world to radically re-think what they do," he said, adding there were "plenty of reasons" for optimism and confidence for the future.
Authors, publishers, agents and translators from around the world will gather from Wednesday in the western German city for the five-day fair, with Brazil as guest of honour.
Gottfried Honnefelder, president of the German Publishers and Booksellers Association, said sales from book stores, e-commerce and department stores grew this year by 0.8 percent until end-September, compared to the previous year.
Taking book store sales alone, the growth was 0.9 percent, he said, adding that although the figures were small, it showed a "trend" with book stores projecting a "new self-confidence" in Germany.