The benchmark index for euro zone blue chips retreated 0.4 percent, while the pan-European STOXX 600, which also includes stocks in the UK and outside the European Union, was down 0.3 percent.
US shares were also expected to open lower, with futures for the S&P 500 and the Nasdaq trading down 0.2 percent and O.3 percent respectively.
Earlier, MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.9 percent after China accused the United States of engaging in bullying over trade, added $60 billion of US products to its import tariff list and reportedly cancelled mid-level talks.
Buoyant dealmaking - with Comcast winning a pay-TV bidding war for Sky in the UK and Randgold Resources' merger with Canada's Barrick Gold - was not enough to defuse fears that the standoff between the two biggest world economies would hurt.
"This is here to stay", commented Adrien Dumas, a manager at Mandarine Gestion in Paris, arguing that because trade is at the core of the Trump administration's agenda, investors should accept that the trade war theme is unlikely to recede any time soon.
"It's a negative and it adds to other issues", he said, pointing to stress in emerging markets or political risk in Italy and Britain.
"Brexit is also weighing on sentiment", he noted.
OIL JUMPS 2 PCT
The UK blue chip index FTSE 100 was down 0.3 percent. The pound rose 0.24 percent to $1.3111 after a fall on Friday when British Prime Minister Theresa May said talks with the EU had hit an impasse.
British opposition leader Jeremy Corbyn said on Sunday he would back a second Brexit referendum if his Labour Party backs the move, heaping more pressure on May, amid speculation that she could opt to call a snap parliamentary election.
The euro rose 0.16 percent close to a three-month peak at $1.1768. The dollar index, which measures the greenback against a basket of major currencies, was last at 94.116, just above its weakest point since early July.
The Japanese yen, which sees fund inflows during times of crisis, was up 0.05 percent, while the trade-sensitive Australian dollar was down 0.18 percent.
Oil prices jumped 2 percent as US sanctions restricted Iranian crude exports, tightening global supply, with some traders forecasting a spike in crude to as much as $100 per barrel.