Greece has introduced a smoking ban that outlaws lighting up in all public indoor areas and prohibits most tobacco advertising.
The country's health ministry says the measures are necessary after partial smoking bans that started eight years ago have largely been ignored.
Some 42 per cent of Greeks over age 15 smoke, well above the European Union average of 29 per cent, according to EU figures.
Harvard University's School of Public Health is advising the Greek campaign and will help gather data in Greek cities to gauge the effect of the ban.
Smokers violating the new law will be fined between €50 and €500, while businesses will be fined between €500 and €10,000.