Time is up to exchange the obsolete franc for France\'s current currency, the euro, Banque de France officials said Friday. Friday was the last day the old notes could be exchanged -- the currency had gone out of circulation at the beginning of 2002 when France began using the euro, Radio France Internationale reported. Banque de France officials estimated about 50 million franc bills worth 600 euros were still in circulation at the end of 2011. \"Many [bills] will never be returned. They\'re either overseas, or destroyed, or forgotten,\" bank Deputy Director Henri Jullien said. Some businesses had been accepting francs since January in a publicity stunt to help people in rural areas exchange the older notes. Francs can only be exchanged at Banque de France locations, which are usually in larger cities, Radio France Internationale reported.