More than 30,000 protesters have taken to the streets of Hannover in northern Germany ahead of a visit by US president Barack Obama.
The demonstrators are concerned about the Trans-Atlantic Trade and Investment Partnership (TTIP) between the US and EU.
The trade negotiations have been carried out mostly in secret but would open up Europe’s public services such as health, education and water to US companies.
Critics fear that EU standards on food safety and the environment would be lowered to be closer to those in the US and that there would be less protection for employees.
One demonstrator said: “The agreements unilaterally benefit big companies and lobby groups, and normal people and their livelihood provisions are pushed into the background and become a tool for furthering the interests of big companies”.
“I have generally always been actively opposed to agreements that in essence are a dispossession of our democracy, and we have to continue to try and fight this,” said another.
Obama argues the agreement would mean “new growth and jobs on both sides of the Atlantic”.
His visit to Germany comes at the end of a six day trip, three days of which were spent in the UK urging voters to remain in the EU.