Background: During the SARS-CoV-2 pandemic, the French Government imposed various containment strategies, such as severe lockdown (SL) or moderate lockdown (ML). The aim of this study was to evaluate the effect of both strategies on severe trauma admissions and ICU capacity in Ile-de-France region (Paris Area). Main text: We conducted a multicenter cohort-based observational study from 1 st January 2017 to 31th December 2020, including all consecutive trauma patients admitted to the trauma centers of Ile-de-France region participating in the national registry (Traumabase®). Two periods were defined, the "non-pandemic period" (NPP) from 2017 to 2019, and the "pandemic period" (PP) concerning those admitted in 2020. The number of ICU beds released during 2020 pandemic period (overall period, SL and ML) was estimated by multiplying difference in trauma admissions by the median length of stay during the same week of pandemic period (ICU day-beds in 2020). A 15% yearly reduction of trauma patients was observed during the PP, associated with the release of 6422 ICU day-beds in 2020. During SL and ML, the observed decrease in trauma admission was respectively 49 and 39% compared with similar dates of the NPP. The number of beds released was 1531 days-beds in SL and 679 day-beds in ML. Those reductions respectively accounted for 4.5 and 6.0% of the overall ICU admission for COVID-19 in Ile-de-France. Conclusion: The lockdown strategies during pandemic resulted in a reduction of severe trauma admissions. In addition to the social distancing effect, lockdown strategies freed up an important number of ICU beds in trauma centers, available for severe COVID-19 patients.