Background The COVID-19 outbreak requires a permanent adaptation of practices. Cardiopulmonary resuscitation (CPR) is also involved and we evaluated these changes in the management of out-of-hospital cardiac arrest (OHCA). Methods OHCA of medical origins identified from the French National Cardiac Arrest Registry between March 1st and April 31st 2020 (COVID-19 period), were analysed. Different resuscitation characteristics were compared with the same period from the previous year (non-COVID-19 period). Results Overall, 1005 OHCA during the COVID-19 period and 1620 during the non-COVID-19 period were compared. During the COVID-19 period, bystanders and first aid providers initiated CPR less frequently (49.8% versus 54.9%; difference, − 5.1 percentage points [95% CI, − 9.1 to − 1.2]; and 84.3% vs. 88.7%; difference, − 4.4 percentage points [95% CI, − 7.1 to − 1.6]; respectively) as did mobile medical teams (67.3% vs. 75.0%; difference, − 7.7 percentage points [95% CI, − 11.3 to − 4.1]). First aid providers used defibrillators less often (66.0% vs. 74.1%; difference, − 8.2 percentage points [95% CI, − 11.8 to − 4.6]). Return of spontaneous circulation (ROSC) and D30 survival were lower during the COVID-19 period (19.5% vs. 25.3%; difference, − 5.8 percentage points [95% CI, − 9.0 to − 2.5]; and 2.8% vs. 6.4%; difference, − 3.6 percentage points [95% CI, − 5.2 to − 1.9]; respectively). Conclusions During the COVID-19 period, we observed a decrease in CPR initiation regardless of whether patients were suspected of SARS-CoV-2 infection or not. In the current atmosphere, it is important to communicate good resuscitation practices to avoid drastic and lasting reductions in survival rates after an OHCA.