It wasn't just in Niger. Pretty much every leader from a muslim majority country has condemned the Charlie Hebdo staff, some going so far as to declare death an appropriate punishment (fanatical bundle of stickss applying retroactive international death penalties to people already killed by other fanatical bundle of stickss, lol). Most are just echoing the feelings of the majority of their constituents, as politicians do. Erdogan's statements aren't some sort of radical fringe view. They're the base. Behold, the worldwide "moderate" muslim.
There were also protests in Pakistan and Algeria, with a consulate attacked. Algeria is really the big one, in my opinion. It's the source of most muslim immigration to France, with Morocco following close behind. AQMI is mostly algerians. They've been fighting a civil war with their government for decades.