The decision was made after Breton spoke with Alphabet CEO Sundar Pichai and YouTube CEO Susan Wojcicki.
The company said it had seen only a few spikes in usage so far but decided to take measures to reduce stress on the system.
“We are temporarily committed to changing all traffic in the European Union to the standard definition by default,” the company said in a statement.
A spokesperson said the decision includes the UK and will initially be for a period of 30 days, and is subject to review.
“I very much welcome the initiative taken by Google to maintain the smooth functioning of the Internet during the Covid-19 crisis,” Britton said in a statement.
Telecom providers in Europe, from Vodafone to Deutsche Telekom, have seen a spike in data traffic in recent days, forcing Breton to issue a precautionary notice before the network suffers a downturn.
For its part, Netflix said it will cut bit rates, which determine the quality and size of its audio and video files, in all its European streams for a period of 30 days, which means reducing traffic on European networks by about 25 percent.