I m a young Muslim born in France and I'd like to know if I could work in the French police. Isn't it in contradiction with our religion? Please response with references to Qur'an and Sunnah.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

There is a clear Hadith that proves the prohibition of working as policeman under unjust rulers. It is narrated in Sahih Ibn Hibban from Abu Saeed and Abu Hurairah that the Prophet (Sallallahu Alaihi wa Sallam) said: "Some day, your Emirs will show favour to wicked people and delay performing the prayer from its fixed times. So, whoever among you sees such a thing, should not take the post of a monitor, policeman, revenue officer or a treasurer." [ Sheikh al-Albani graded this Hadith as sound in his book 'Silsila al Sahihah'. If the prohibition of holding such jobs applies to a Muslim government then with greater reason it becomes applicable to a non-Muslim government.
It is common knowledge that laws of such government protect dissoluteness and provide security for all kinds of shameless acts. Therefore, a Muslim should not work under such governments as a policeman. A Muslim cannot work for the safety of nightclubs, bars, dance halls, brothels, etc. Therefore, the questioner should seek a lawful job that is not contrary to his faith and religion. Allah says: {And whosoever fears Allâh and keeps his duty to Him, He will make a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine……..} [65:2,3]
May Allah bless all of us.
Allah knows best.