As a 29-year-old French national became the 10th person to be admitted to an intensive care unit after contracting swine flu, Athens City Hall announced that seven special medical centers offering free tests for the diagnosis of the H1N1 virus are now operating in different parts of Athens. The French tourist was in critical condition yesterday, doctors said, noting that he had been admitted to the ICU with serious breathing problems. More than 1,800 people have contracted swine flu in Greece, according to the Health Ministry, though only 10 of these have been described as serious cases. Citizens who believe they might have symptoms of the H1N1 virus can visit one of the Athens municipality’s seven diagnostic centers between 8 a.m. and 6 p.m. daily. The centers are at 78 Solonos Street and in Pangrati, Neos Cosmos, Petralona, Kolonos, Kypseli and Patissia.