At the request of the Ministry of Health, we estimated the number of health events (cases, hospitalizations, and deaths) expected during an influenza pandemic and compared the impact and cost of control measures. We then estimated the weekly number of admissions and hospital days. A Monte Carlo model provided health events (HE) by age and risk group. HE rates were derived from the literature or expert estimates. Vaccination and the use of antivirals for prophylaxis or treatment were compared among at-risk individuals, priority populations for maintaining the functioning of essential services, and the general population. Without intervention, a pandemic could result in up to 20.9 million cases, 0.2 million deaths, and 1.0 million hospitalizations in France. With a case fatality rate of 25%, 1,300 to 86,000 deaths could be prevented depending on the target population and the intervention. Vaccination should be prioritized if the vaccine is available. If not, seasonal prophylaxis is preferable for the priority population, and curative treatment for at-risk groups. The weekly number of hospital admissions could increase by 46% compared to values observed in current epidemics, and the number of hospital days by 132%. This study enabled a comparison of interventions and highlights the important role of antivirals. Its main limitations are a static model and the uncertainties associated with parameter values. Hospital admission and discharge criteria will play a key role in limiting hospital overcrowding. (R.A.)