The Eutelstat balloon is normally tethered in the Parc André-Citroën where it provides a wonderful view over Paris, rising to a height of 150 metres.
It will be closed for maintenance from 1 January until mid-April when a new balloon, that changes colour according to the degree of pollution in the air above Paris, will be installed by the manufacturers, Aerophile. A green colour will indicate that the air is good, orange that it is passable, and red that it is very poor quality.
I just wonder how keen people will be to ride in a balloon that is turning red to indicate that the air they are passing through is polluted.
Source: Développement durable - le journal