Paris - French judges have ended their investigation into the substantial assets of Gabon's late president Omar Bongo and his family, none of whom have been charged, sources close to the case said Wednesday. French prosecutors have been investigating since 2010 whether the fortunes amassed in France by the ruling elites of three oil-rich African countries - Congo Brazzaville, Equatorial Guinea and Gabon - were built up with money siphoned from public coffers. The sprawling investigation saw its first trial this year - that of Teodorin Obiang, vice president of Equatorial Guinea and the son of the president, though only his lawyers turned up in court. His sentencing is due on October 27.In the Gabon probe, authorities last year ordered the seizing of property company SCI Emeraude, which owned a mansion in the chic 16th arrondissement of Paris and a villa in Nice on France's glitzy Cote d'Azur.According to a 2009 report by anti-corruption watchdog Transparency International, which is acting as a civil party in the case, the Bongo family owned at least 33 properties in France, most of them in expensive Paris districts.Together the properties were believed to be worth several hundred million euros, though the full extent of the Bongo family's assets remains unclear.Omar Bongo died in 2009 after four decades in power, leaving his son Ali Bongo to take over.The elder Bongo, along with his late wife Edith and his daughter Pascaline, held shares in the property company and its manager has been charged, but there was insufficient evidence to charge any of the family members, a source close to the case said.Pascaline Bongo, a former foreign minister, is alleged to have been the owner of three Paris apartments and several luxury cars bought in France. She allegedly spent some $1.64 million on watches and jewellery between 2006 and 2007.Investigators are examining possible links between the current president and a Swiss company, Achimmob, which notably owns a Parisian mansion.