[hyakosm]

"CV" is for "Chevaux" (horses) but we're talking "tax horses", a calculation used for a taxation system where more powerful vehicles cost more. The current french formula is 0.00018 * [power in kW]^2 + 0.0387 * [power in kW] + 1.34

https://fr.wikipedia.org/wiki/Cheval_fiscal (current formula, french page)

https://en.wikipedia.org/wiki/Tax_horsepower#France (general explanation)