French counter-terrorism investigators are investigating a dual Russian-Ukrainian citizen who was seriously injured when a homemade explosive device detonated in a hotel on the outskirts of Paris. Emergency services treated the 26-year-old with severe burns on Monday evening, counter-terrorism authorities said on Wednesday. Investigators found materials used in bomb-making at the scene, where one of the explosive devices detonated. The man was taken into custody. Authorities opened an investigation into the man for participating in a criminal terrorist organization, planning to carry out crimi…