The amount of aid may not exceed that of the actual loss of turnover recorded over the period between 1 January and 31 March 2021 in relation to the average turnover achieved between 1 January and 31 March of the years 2017, 2018 and 2019, less the amounts of subsidies intended to compensate for the loss of turnover suffered during the months of January to March 2021 under Decree no. 2020-371 of 30 March 2020 relating to the solidarity fund for businesses particularly affected by the economic, financial and social consequences of the spread of the covid-19 epidemic and the measures taken to limit this spread, and decree no. 2021-310 of 24 March 2021 instituting aid to compensate for the fixed costs not covered by companies whose business is particularly affected by the covid-19 epidemic.