Experiences from over a decade of action camps and mobilisations have
shown that when we come together for mass action it is important to
collectively organise the capacity to deal with medical emergencies. It
has also shown that when we take to the streets to protest against police
and state brutality and social control, we are often putting ourselves at
considerable risk. The French police in particular are known for their
excessive use of tear gas and concussion grenades. It is therefore

see report at http://lille.indymedia.org/spip.php?page=article&id_article=16465

Here is a translation of the text from the article:

21st May in Calais : the prefect [of the Calais area] Bousquet sends his troops. The prefect and his army responded to the call [for a demo] by SOS soutien aux Sans Papier [SOS Support the Undocumented]
Calais was besieged by garde-mobiles [national guard] and the CRS [riot police] at strategic locations.