Schema of the facts:

bareme_km(Annee, Vehicule, Classe, tranche(Min, Max), formule(Coef, Constante))

• Annee: year of the tax return (annee de declaration), 2022..2026. The kilometres are those driven the previous year (see annee_revenus/2).
• Vehicule: automobile, motocyclette (more than 50 cm3) or cyclomoteur.
• Classe: fiscal horsepower class (see classe_puissance/3).
• tranche(Min, Max): the band applies when Min < Km =< Max (first band: 0 =< Km =< Max). Max = inf for the last band.
• formule(Coef, Constante): Montant = Km * Coef + Constante (euros).

Electric vehicles: +20 % on the amount (CGI, annexe IV, art. 6 B, II), option electrique(true) of frais_km/6.

 classe_puissance(+Vehicule, +CV, -Classe) is semidet

Maps a fiscal horsepower (integer CV) to the class used by the scale. Cyclomoteurs have a single class (toutes), CV is ignored.

 frais_km(+Annee, +Vehicule, +CV, +Km, -Montant) is semidet

Deductible amount in euros (rounded to the cent) for Km professional kilometres, thermal / hybrid / hydrogen vehicle.

 frais_km(+Annee, +Vehicule, +CV, +Km, +Options, -Montant) is semidet

As frais_km/5. Options: electrique(true) applies the 20 % increase for 100 % electric vehicles.

 annee_revenus(?AnneeDeclaration, ?AnneeRevenus) is nondet

The 2026 scale (declaration year) applies to 2025 income/kilometres.

 source_bareme(?AnneeDeclaration, ?Source) is nondet

Official text against which each year was cross-checked.

 bareme_km(?Annee, ?Vehicule, ?Classe, ?Tranche, ?Formule) is nondet

135 facts: 5 years x (15 automobile + 9 motocyclette + 3 cyclomoteur).