The Eiffel Tower is barely seen through the smog from Paris, March 14, 2014. Nearly three-quarters of France is under alert in what the European Environment Agency says is the worst air pollution since 2007.

Thick smog has settled over Paris today in one of the worst bouts of pollution the country has seen since 2007, according to the Associated Press.

Parisians were given free access to public transportation around the region for the next three days, including free rides on Paris's bike share program, in an effort to reduce the smog.

Parisian authorities advised "children and sensitive people to avoid doing sports and follow their medical treatment" during the spell, according to flashing messages displayed throughout the city.