I'm currently working on a problem that says the following :
At first we had a number N of firms in perfectly competitive industry,the exercice gives us the total cost and the Market Demand with p as the market price . After studying this case ( Consumer surplus, market equilibrum and firm profit ) the exercice adds the following :"The government decides that each firm in the industry must pay a license fee of 12 per period, whether they produce an output or not " and from this we should find the market price and what output maximizes firm profit and level of firm profit. I don't know how to interpret the license fee, is it a tax? the only exercises i've seen so far are with a per unit tax applied to the producer .