To limit the transmission of COVID-19, nationwide lockdown was imposed in France between March, 17(th) and May, 10(th) 2020. This disruption in individuals' daily routines likely altered food consumption habits. We examined how changes in food choice motives related to changes in nutritional quality during the lockdown compared to before. A convenience sample of 938 French adults completed online questionnaires on the Qualtrics platform at the end of April 2020. Participants were retrospectively asked about their food choice motives and food consumption during the month before and in the first month of the lockdown. The importance of nine food choice motives was assessed: health, convenience, sensory appeal, natural content, ethical concern, weight control, mood, familiarity, and price, scoring from 1 to 4. Food intakes were recorded using a food frequency questionnaire including 110 foods, 12 non-alcoholic beverages and 4 alcoholic beverages. Adherence to the French dietary recommendations before and during the lockdown was estimated using the simplified PNNS-GS2 score, scoring from -17 to 11.5. The nutritional quality of diet was lower during the lockdown compared to before (-0.32, SD 2.28, p<0.001). Food choice motives significantly changed and an increase in the importance of weight control was associated with increased nutritional quality (β=0.89, p<0.001, partial η(2)=0.032), whereas an increase in the importance of mood was associated with decreased nutritional quality (β=-0.43, p=0.021, partial η(2)=0.006). The lockdown period in France was related to a decrease in nutritional quality of diet on average, which could be partly explained by changes in food choice motives. The lockdown was indeed related to modification of food choice motives, notably with an increase of weight control, health, natural content and ethical concern.