Some of the targeted animals have lost their ears, genitals and even been disembowelled in the attacks.
It is believed the horses’ ears are being collected as ‘trophies’.
More than 30 horses have been slaughtered or maimed around the country this year, with the latest crime taking place this morning.
Police are not certain whether the spate of killings is the work of one person or whether copycat criminals have joined in.
Some fear the attacks may have been committed by a ‘cult’.
Officers are searching for two suspects in Losne, near Dijon, after a horse was injured in its flank at around 1am today.
The Gendarmerie de l’Yonne has released an e-fit of a suspect spotted at the scene of an attack in Yonne, north-west of Dijon, last month.
In another vicious crime in Saint-Vallier last month a pony was found with its face sliced off.
An autopsy revealed its diaphragm had ‘exploded’, meaning people may have ‘jumped’ on the animal.
In a separate incident a week before a horse was found ‘disembowelled’ in Vaucluse in the Provence-Alpes-Côte d’Azur region.
A police spokesman told Le Journal de Saone-et-Loire : “Human intervention leaves little doubt. All the means of the technical and scientific police are used to try to find the perpetrator (s) of these acts.”
Agriculture Minister Julien Denormandie previously said: “All branches of the state are mobilising to get justice done.
“There is clearly a professionalism, people acting with a certain level of technique.”
Johan Papillon, a French farmer from Eure-et-Loir, described the criminals as ‘barbarians’ after they sliced his horse’s throat.
Serge Lecomte, president of the French Equestrian Federation, told AFP: “It is cruel savagery of a kind we have rarely seen before.
“Is it a cult? Cruelty towards animals is the precursor to cruelty towards humans.”
Luckily the animal survived although it required 300 stitches to its neck.