In March 2020, as the coronavirus disease 2019 (COVID- 19) pandemic was spreading across the globe, many countries have implemented unprecedented lockdown measures. But how populations did react to these measures? We examined the case of France. Our aims were threefold: assessing some aspects of their impact on French's daily living conditions; investigating their attitudes toward the lockdown; investigating the factors associated with these attitudes. Methods A cross-sectional online survey was carried out 10 days after the nationwide lockdown (from March 27th to March 29th 2020), among a representative sample of the mainland French population aged 18 and over. A quota sampling method was applied to achieve a sample of 1012 respondents. We used a cluster analysis to obtain contrasted attitudinal profiles, and logistic regressions to investigated which factors were associated to these profiles. Results After 10 days of lockdown, there were already significant consequences regarding respondents' living conditions and mental health. Most respondents supported the current lockdown. However, it appeared as a stopgap measure due to a lack of alternatives, and a large majority acknowledged its heavy drawbacks. We found three contrasted attitudinal profiles: full support (38%), strong but critical support (31%), limited support (31%). Regarding respondents' SES, low-income and low-education respondents were more likely to display critical or limited support to the lockdown, as well as those who reported deteriorated living conditions or psychological distress. Conclusions In France, the large public support to the lockdown was fragile. First, it was a critical consensus anchored in current controversies and recent social struggles. Second, it was weaker among people with a lows SES, especially since the lockdown have exacerbated preexisting social inequalities.