At first glance the bright yellow circles appearing on images of a famous French fortress look like they have been faked.

But contrary to what some might be wishing in Carcassonne, south-west France, they are very much rooted in reality.

The yellow aluminium strips were added to the town’s medieval fortress to mark 20 years since it was given Unesco World Heritage status.

Swiss artist Felice Varini, the creator of the installation, said that they fit perfectly with the monument’s grey walls.

But not everyone agrees. A petition calling for the circles to be removed has attracted nearly 2,000 signatories.

“It is very clear for me, and, I think, for many others, that these circles, which bring nothing artistically, only defigure,” reads the text encouraging people to support the petition.

There have been reports that the yellow circles, inaugurated on May 4 and set to stay in place until September, have already been vandalised.

Varini, responding to the criticism, said: “I have often met this type of reaction. At first there is incomprehension and then opinions change little by little.”

The fortress has a double row of fortified walls that run for three kilometres and include 52 watchtowers.

It is a major tourist attraction and is visited by three million people a year.

Photo copyright: Felice Varini. Photo: André Morin