The wanton destruction took place on June 26th when officers were patrolling along the Cours de Charlemagne in the centre of the city.
When the police stumbled upon the plants they thought they had wandered across an illicit cannabis plantation in the heart of France's second city.
They wasted no time and jumped into action pulling out the plants one by one across an area of 400 square metres, reported local newspaper Le Progres.
You can probably imagine how stoned, sorry stunned, the police were when they were informed the plants were actually there in the name of art as part of an instillation titled “waiting room”.
And more to the point the plants weren't cannabis at all, but a mixture of hemp, barley and linen that had been planted as part of the event "Lyon Architecture Biennial".
Fruit from the plants were set to be harvested on Saturday when the event was due to end.
For the red-faced police, the fault lay with the organisers who they argue should have put up a sign to indicate it was artwork.
But to be fair to officers the hemp plant looks remarkably similar to the cannabis plant, except it's not quite so potent.