The key strategy is to switch from the flat-rate calculation to the actual-cost calculation when business use predominates. The actual-cost calculation applies the private-use percentage to the vehicle’s actual costs, which reduces the taxable base for social security purposes as long as personal trips are limited. For the switch to be accepted by the social security authorities, you must document the business-to-personal breakdown for each trip and retain the supporting documents for five years. Software like Fleeti automates this process using data from the connected vehicle, applies the official scale set forth in the decree of February 25, 2025, and selects the most advantageous method for each employee on a monthly basis.

The estimated savings range from 1,500 to 2,952 euros in employer contributions per vehicle per year, depending on the fleet profile, engine type, and frequency of business use. For employees, switching to the actual mileage method can result in up to 2,600 euros in additional annual taxable income, at no extra cost to the company. The exact amount depends on the vehicle’s purchase price, whether fuel costs are covered, and the ratio of business kilometers to total kilometers. A simulator allows you to estimate the savings for your fleet before making the switch.

The decree of February 25, 2025, significantly raised the flat rates used to calculate the vehicle AEN for the first time since 2002. For a gasoline-powered vehicle purchased less than five years ago, the rate (excluding fuel) increases from 9 to 15 percent of the total cost, including tax. For a vehicle under a long-term lease (LLD) or lease-to-own agreement (LOA), the rate increases from 30 to 50 percent of the total annual cost. Conversely, 100 percent electric vehicles with an eco-rating benefit from an increased deduction of 70 percent instead of 50 percent, capped at 4,582 euros per year and applicable through December 31, 2027. The new rates apply to vehicles assigned on or after February 1, 2025; vehicles already assigned prior to that date will retain the old rates until they are reassigned.

Not always. The actual-mileage calculation becomes more advantageous when business use is the primary purpose—typically when business mileage accounts for 60 to 70 percent of total mileage, depending on the vehicle’s engine type and cost. For a vehicle used infrequently for business, or for a fleet of executive vehicles used primarily for personal purposes, the flat-rate option is sometimes simpler and even more cost-effective. Best practice, therefore, is to compare the two methods monthly for each employee, rather than choosing a single method for the entire fleet. This is the automatic decision-making process that Fleeti performs every month.

Social security authorities require three elements: traceability for every business and personal trip, documentation of the vehicle costs taken into account, and retention of supporting documents for five years. Failure to comply results in the authorities reclassifying the calculation as a flat rate, with back payments of contributions and penalties. The Court of Cassation upheld this strict standard in a ruling handed down in January 2025. Fleeti automatically generates the required documentation: a monthly summary per employee, a breakdown of business and personal mileage, application of the current rate schedule, and time-stamped archiving for five years. The file can be exported with a single click in the format requested by the inspector.

The flat-rate method applies a percentage of the vehicle's cost (15 percent of the purchase price, including tax, for a gasoline- or diesel-powered vehicle less than five years old; 50 percent of the annual cost for a long-term lease). The actual method applies the private-use allocation to the vehicle’s actual costs (depreciation, fuel, maintenance, insurance, financing). The flat-rate method is quick to apply; the actual method requires mileage tracking but reduces the net benefit as soon as business use becomes predominant. The choice is made on an employee-by-employee basis and may vary from month to month.

The actual AEN is included in the monthly DSN as a standard benefit in kind: category S21.G00.51 (Compensation), code 30 (benefit in kind). There is no specific field in the DSN to distinguish between the flat rate and the actual amount; it is the internal documentation (method, kilometers, supporting documents) that verifies the method in the event of an audit. Fleeti pre-formats the values and provides the supporting details, ready to be integrated into your payroll software.

Vehicles assigned before February 1, 2025, will retain the old rates until their next reassignment. A combustion-engine vehicle purchased in 2024 and still assigned to the same employee will continue to be calculated at the flat rate of 9 percent (or 12 percent including fuel), without applying the new rates. The new 15 percent rate (or 20 percent including fuel) applies only to vehicles assigned or reassigned on or after February 1, 2025. The switch to the actual-cost method remains possible at any time, regardless of this date.