Paris has been hit with its worst air pollution in over a decade. The smog has reached levels of pollution that are over three times the internationally-agreed safety limit - and worse than Beijing's.
The air pollution has been blamed on a combination of factors - vehicle emissions, the use of wood fires for heating, and windless conditions.
As the smog continues for the third winter night, authorities are taking desperate measures.
On alternating days, cars with odd and even-numbered licence plates have been banned from entering the city centre.
This is only the fourth time in 20 years that Paris has imposed this car ban. It is also the first time it has been applied on consecutive days.
Public transport has also been made free in an effort to reduce vehicle use, and older vehicles which pollute the most will be permanently banned.
Further measures are also being contemplated, however the grey haze of smog seems set to continue.
"As long as the meteorological situation remains the same and emissions remain the same, we will not see the end of the pollution spike," Paris prefect Michel Cadot says.