European stocks fall at open

European stock markets fell at the start of trading on Tuesday as Greece reached a deal over a third bailout and after China devalued the yuan to boost its economy. London's benchmark FTSE 100 index dropped 0.41 percent to 6,708.80 points compared with Monday's close. "An agreement was reached," the source told AFP, with Finance Minister Euclid Tsakalotos briefly telling reporters that "one or two details" remained to be worked out during the day.