This post is part of our special coverage Tunisia Revolution 2011.

Tunisia's netizens and activist community were shocked on April 9, 2012, by the police response to a planned protest to mark Martyrs’ Day. It came a day after a smaller protest by jobless young people was attacked by the police.

The protesters planned to challenge the ban on protesting on Habib Bourguiba Avenue by starting their demonstration on Mohamed V Avenue. Police responded by using tear gas, batons and electric batons to disperse them. Some members of the National Constituent Assembly, journalists, bloggers, lawyers and activists were harshly beaten. Netizens expressed their anger, shock and sense of déja-vu.

Protesters encircled by police in Tunis on April 9, 2012. Image by Flickr user Amine Ghrabi (CC BY-NC-SA 2.0).

Tear gas spreads through the air. Image by Flickr user Amine Ghrabi (CC BY-NC-SA 2.0).

Global Voices author Afef Abrougui tweeted:

Protesters flee tear gas in Tunis. Image by Lina Ben Mhenni (CC BY-NC-ND 3.0).

Tear gas engulfs the air in Tunis. Image by Lina Ben Mhenni (CC BY-NC-ND 3.0).

Twitter user Tunisienne Libre (@Fleursdecactus) tweeted that the aggression spread to other streets:

@Fleursdecactus: C'est le chaos à Jean Jaures, av. de Paris, rue de Marseille… Poursuites, agressions, lacrymo.

Protesters move from a street to another in Tunis. Image by Lina Ben Mhenni (CC BY-NC-ND 3.0).

Police clash with protesters at Mohamed V Avenue in Tunis. Image by Lina Ben Mhenni (CC BY-NC-ND 3.0).

Slim Amamou, prominent blogger and founder of the Tunisian Pirate Party, described the situation:

@slim404: #9avril Le nombre de bras fracturés est anormal. Il y a qlq chose qui a changé dans l'équipement ou les méthodes de la police

Fatma Riahi, alias Fatma Arabicca, a prominent blogger and the co-founder of the Association of Tunisian Bloggers, was beaten by riot police and hospitalized. In this video [ar] she explained what happened:

Afef Abrougui criticized the government's justification for banning protests on Habib Bourguiba Avenue, which was to protect businesses and attract tourists:

@AfefTN: protesters, MPs, journalists, activists & paramedics were assaulted 2day in #Tunis | a good way to attract tourists u gov of fools #9avril

Blogger Keyser Söze wrote a post entitled “Pandora's Box”:

Le 9 avril 2012 restera un jour triste  dans la mémoire de tout tunisien.  Il portera  à jamais la marque de l’ingratitude des autocrates en poste envers le  peuple qui les a libérés.

He added:

Toute la panoplie de la répression de l’aire dictatoriale  a été employée pour casser du Tunisien.  Ils ont même eu recours à l’aide de milices inconnues comme à la belle époque.

The following YouTube video by TunisiaTalks shows police chasing protesters and their brutality towards them.

Mustapha Ben Jafar, the President of the National Constituent Assembly asked the government [fr] to begin an investigation to find out who was responsible. On television the president Moncef Marzouki apologised for the high level of violence employed against protestors.

This post is part of our special coverage Tunisia Revolution 2011.