Corporate car fleets account for 16% of all light-duty vehicles in France, and about 25% of their total CO2 emissions. They also account for 40% of new light-duty vehicle sales, and close to 50% of new battery-electric vehicle sales. Yet, the environmental performance of corporate vehicles differs widely between passenger cars and light commercial vehicles. The former are heavily taxed based on their CO2 emissions under both, the ‘malus’ scheme (environmental penalty upon initial registration) and the TVS scheme (annual circulation tax), whereas the latter are exempt from all CO2-based taxes. On the other hand, both passenger cars and light commercial vehicles in corporate car fleets are eligible to the ‘bonus’ scheme (environmental incentive upon initial registration), and to the registration tax rebates for alternative-fuel vehicles. This paper discusses the influence of tax policy on the CO2 emission levels of, and demand for alternative-fuel vehicles by, corporate car fleets in France. We present the main tax schemes that have a probable influence on the choices of corporations with regards to the CO2 emission levels and drivetrain technology of the vehicles they purchase and use (past and present terms and conditions: scope, tax base, etc.), based on a historical review of tax policies. Besides, we provide a preliminary assessment of the expected effectiveness of the various tax schemes listed, based on the magnitude of the costs (or benefits) they impose on corporations, using a TCO (total costs of ownership) approach. Finally, we discuss the similarities and differences in the terms and conditions of the schemes reviewed, and the relative strength of their incentive effects on corporate car fleets. Through unravelling the complexity of the tax policy framework, we highlight several challenges pertaining to the lack of legibility and/or consistency among tax schemes, and the existence of inertia, which hinder the effectiveness of tax policy in fostering the uptake of low-emission vehicles by corporate car fleets. We argue for an overhaul of the tax policy framework that applies to corporate car fleets, which would provide an opportunity to clarify the objectives of policy-makers with regards to the environmental impacts of fleets, and to design more efficient policies (tax or otherwise).