Traditions & Customs
Visitors are treated as kings in Niger (there is a Koranic proverb to that effect), so be careful not to abuse the hospitality you will be shown. For the most part, try to accept all the small tokens and gestures (cokes, tea, small gifts, etc.) that are offered to you during your time in Niger. It really isn't good to refuse too much and don't think "these people are too poor to give me these things". That is offensive as taking good care of guests is a point of honour and gives people great pleasure. Don't comment out loud when you see poverty or things in disrepair and please don't remind Nigeriens about how poor their country is.
Dress conservatively, which means no shorts, no skirts above the knees, and no tank tops. For women, dressing revealingly can be seen as very offensive, even in Niamey. Also, dress nicely, as clothes determine how well you are treated back.
Avoid drunken behaviour, since alcohol is prohibited in the Muslim religion and greatly frowned-upon in Niger.
Always ask people, especially camel drivers, market sellers, and the elderly, before taking a photograph. Many Nigeriens still find it offensive.
Slavery is still relatively common in the central areas, away from the towns. You can generally spot slaves by the unadorned, solid ankle bracelets on both feet, which look like manacles and may well serve that purpose. Unless you feel particularly brave, discussion of the subject with either victims or perpetrators is probably best avoided.