Three lawyers accused her of committing an obscene act in public, “inciting debauchery and temptation”, and “spreading vice in ways that violate established norms in Egyptian society.”
The pictures of the star, who is known for her role in a number of popular Egyptian TV series, left social media users divided, with some calling her names and other defending her right to wear what she wants.
“This dress and design is called ‘I forgot my trousers while going to be honoured,” wrote one Twitter user.
Another Twitter user writing under the name Zakaria MJ frowned at the criticism.
“Rania Youssef is looking gorgeous,” he wrote in a message in English. “I don’t get why everybody is mad at her.”
Ms Youssef had just finished shooting for the film “Aswar Aaliya” (High Fences), in which she plays the role of a famous artist who is sent to prison.