21 September is Peace One Day, a U.N. day of ceasefire and non-violence around the world. A day to bring peace into your classroom!
On the Peace One Day website, you can find teaching packs in English (and also Arabic, Chinese, French, Russian and Spanish if your colleagues would like to join in!) They include films and of work on non-violence. The Global English pack has a section that would fit well into a Mythes et Heroes or general citizenship theme, on peacemakers like Martin Luther King, Rosa Parks and Mahatma Gandhi.
This introductory film can get you started.
Why 21 September?
More advanced students could watch part of Jeremy Giller's inspiring TED Talk about how he got the idea of the project and how he persevered. He explained, among other things, the significance of the date he chose, which links the personal and the global.