The French anti-terrorism prosecutor’s office has opened an investigation into a Russian-Ukrainian man who was seriously injured when a homemade explosive device detonated. The 26-year-old is to be remanded in custody, the public prosecutor’s office announced in Paris on Friday. The exact plans of the man and others who may have been involved are now to be investigated. According to initial investigations, the man had only arrived in France a few days earlier. In a hotel in Roissy near Paris Charles-de-Gaulle International Airport, he had seriously injured himself while making explosive device…