Brussels said the firm failed to meet EU guidelines on price transparency, with some prospective customers seeing prices increase as they proceeded with making a reservation.
It also said the terms did not give consumers adequate protection in the event of a booking cancellation by the property owner.
"If the company's proposals are not considered satisfactory, consumer authorities could decide to resort to enforcement measures," it said.
In a decade, San Francisco-based Airbnb has grown into a multi-billion dollar firm competing with hotels by linking online consumers with property owners offering attractive prices.
The commission has been cracking down on what is sees as risks for European consumers using the services of US internet giants such as Facebook, Google, Amazon and Uber.
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)