European stocks are set to open slightly higher Tuesday morning despite an escalation of global trade tensions during the previous session.The FTSE 100 is seen up by 4 points at 7,289; the CAC 40 is set to open up by 9 points at 5,794 and the German DAX is seen up by 40 points at 13,011; according to IG.President Donald Trump announced tariffs on steel and aluminum imports from Brazil and Argentina on Monday — sparking further global trade tensions.Furthermore, the U.S. trade representative also said Monday that it could put duties of up to 100% on certain French products. This is on the back of France’s decision to apply a tax on digital companies. The U.S. trade office concluded that the French levy is harmful to U.S. tech companies.Meanwhile, investors are monitoring several high-level meetings as NATO leaders gather in the U.K. to celebrate the 70th anniversary of the organization. Prime Minister Boris Johnson is receiving German Chancellor Angela Merkel, French President Emmanuel Macron and Turkish President Recep Tayyip Erdogan.On the data front, there will be euro zone producer prices due at 10 a.m. London time. There are no corporate earnings to note Tuesday.