Background: Multiple psychological consequences of the COVID-19 outbreak and quarantine have been described. However, there is a lack of global conceptualization. We argue that the stressful aspects of the situation, the multiple environmental consequences of the outbreak, and the diversity of symptoms observed in such a situation, suggest that Adjustment disorder (AD) is a promising way to conceptualize the psychological consequences of the outbreak and quarantine. The first aim of the study was to validate the French version of the ADNM. The second aim was to set out adjustment difficulties resulting from COVID-19 outbreak and quarantine. Method: We recruited 1010 (840 women, 170 men) who consented online to participate. They filled out the French ADNM, visual analogic scales, HADS, IES, and the COPE, to evaluate coping strategies. Results: We confirmed the factor structure of the ADNM and we found good psychometric properties. We found that 61.3% of participants presented an adjustment disorder related to COVID-19 outbreak. We found multiple risk factors and protective factors to AD due to quarantine and outbreak. We also identified the coping strategies negatively and positively associated with AD. Conclusion: Adjustment disorder is a relevant concept to understand psychological manifestations caused by quarantine and outbreak. The French ANDM has good psychometric properties to evaluate such manifestations. The association between coping strategies and AD symptoms suggest that CBT may be the best intervention to help people suffering from AD.