What appeared to be more than 30 white wedding dresses were hung from nooses, strung up between the palm trees.
Lebanese law currently allows a rapist to be exonerated if he marries his victim.
The activists are pressing to have the legislation abolished at an upcoming session of parliament.
Minister for Women's Affairs Jean Oghassabian described the article as being "from the stone age".
"There are 31 days in a month and every single day, a woman may be raped and forced to marry her rapist," said Alia Awada from the non-governmental organisation Abaad.