The method involves transmitting an additional digital content e.g. cinema film, from a transmitter system (2) towards a receiver (3) by temporarily liberated bandwidth, where the additional digital content is diffused in a data transmission network (1) in a continuous manner with a variable flow, independent from a request to obtain the additional digital content in return. The additional digital content is locally stored in the receiver. An independent claim is also included for a system for diffusing an additional digital content from a transmitter system towards a receiver in a data transmission network.