Responding to an urgent request by the authorities of Mali, France launched in January 2013 “Operation Serval” against several terrorist armed groups. The French troops were assisted by a Chadian contingent and by forces progressively deployed by other African countries within a UNSC authorized African force (resolution 2085). While the French and African military Operations in Mali were clearly legal, they raise important questions of jus ad bellum in relation with the two legal arguments put forward to justify them: intervention by invitation and UNSC authorization. In this paper we first discuss the general rules of international law applying on intervention by invitation. We explain that such an intervention could sometimes be contrary to the principle of self-determination and we propose a purpose-based approach. We then apply these rules to the situation in Mali and conclude that the French and Chadian interventions were legal because, on the one hand, the request was validly formulated by the internationally recognised government of Mali and, on the other hand, their legitimate purpose was to fight terrorism. The UNSC approved this legal basis and “helped” France and Chad appeal validly to it by listing the enemy as “terrorist groups”. It gave its “blessing” to these interventions, without authorizing them and observed the events with relief. The adoption of resolution 2100 on 25 April 2013 raises new legal questions. The Council creates a UN peace enforcement mission in Mali, MINUSMA, which has a robust use of force mandate. Created just a few weeks after the DRC “Intervention Brigade”, this force seems to indicate an ongoing evolution (revolution?) in UN peacekeeping, notwithstanding the assurances by some UNSC member States that MINUSMA will avoid “offensive counter-terrorism operations”. At the same time resolution 2100 gives a restricted use of force mandate to France (to protect MINUSMA), without challenging the legal validity of intervention by invitation for all other tasks! The conflict in Mali might thus remain for some time yet between the latitude of UNSC authorization and the longitude of unilateral intervention by invitation.