As a means of identifying the alleged murderer, Tango was called to the stand, where the suspect threatened him with a bat.
The idea was that Tango would start barking, or show some other sign that he recognised the killer.
In a preliminary hearing earlier this month, a second dog of the same breed and age called Norman also summoned to undergo the same test.
It led to protests from the suspect’s lawyer, Gregoire Lafarge, who said: “So if Tango lifted his right paw, moved his mouth or his tail, is he recognising my client or not.
“I find it very troubling for the French legal system. If a judge ignores the demands of reason and surrounds himself with experts who are unreasonable, well the system becomes very dangerous.”
However, the entire episode turned out to be a total failure, with neither Tango nor Norman showing any interest in the man with the bat, or in the rest of the court proceedings.
In 2008, a dog named Scooby created legal history by appearing as a witness in a murder case.
The animal’s 59-year-old owner had been found hanging from the ceiling of her Paris flat.
Police believed it was suicide but her family say that it was murder, and Scooby was in the flat at the time of the death.
During a preliminary hearing in the city, the pet was led into the witness box by a vet, but his barking proved inconclusive.
Despite this, French judge Thomas Cassuto praising the animal for his “exemplary behaviour and invaluable assistance”.