You may not set up a street stall without filing a notification.
Literal
Notification without [to-に] street [on-に] opening-shop doing must-not.
届け出なしに ('without filing a notification') uses 届け出 ('notification, filing') + なしに ('without'). 出店してはならない ('must not open a shop') uses ~てはならない, the formal prohibition pattern. 路上に ('on the street/road') sets the location. Official/legal register for municipal regulations.