Certainly a good argument can and has been made that the play is feminist in nature. The female characters are intelligent and bawdy, feeling there is nothing wrong with their sexual behavior. They aren't the property of the male characters in the play, and Behn, the playwright, uses her women to make fun of society during the Restoration period. During this time, women were either pure and chaste, or they were loose and lewd. Behn's females are strong women who have the courage to defy a patriarchal society that allows men to determine how a woman should behave in proper society.
Behn's feminist views are more developed in Part II where marrying for money is considered to be the same as having sex for money. She makes fun of arranged marriages and marriage in general, showing the hypocrisy of men in marriage. There is no doubt that Behn is making fun of a society that turns women into objects of possession, who are incapable of intelligent thought.
For more of an in-depth look at this play as feminist in nature, go to the enotes site below.