The commission may make rules and regulations for the government and use of the parks, open spaces, boulevards, parkways and roadways, and enforce the same by fixing for the violation thereof penalties, not exceeding fifty dollars for each offense. All rules and regulations shall be plainly printed and posted within the parks and public places or on the boulevards and other highways. The commission may sue for and collect the penalty so fixed in an action at law in any court of competent jurisdiction. All fines and penalties recovered shall be used by the commission for the same purposes and in the same manner as its other funds.