At the border, a tout makes it easier, sometimes necessary if the lines are long etc.
My fav tout is Hamida +222 47403323
he has a sense of humour and is very efficient
three years ago I had the family in the car and there was a hundred Senegambian car dealers before us, things were getting nasty. But he took us through in 30 minutes. So money well spent!
going rate used to be 20 euros but I think they may be getting greedy at the border now, which may spell trouble if it goes on unchecked
Hamida even helped me hide the whiskey inside the back door in nomansland after I had broken my arm last year.
Don't exchange more then you need at the border, you can get a much better rate in Nouakchott, esp at the grand marché.
When in Nouakchott why not visit Ahmed Fall's famed record store, le Saphire d'Or Saphire D'Or - sahelsounds
From afrobeat to zouk: the Mauritanian home of rare African sounds | World news | The Guardian
Ahmed Fall was the first rock musician in Maure, long time ago, still a great poet and singer
https://www.youtube.com/watch?v=n5c468ibHAg
In Mauretanie there is the division between maures and blacks that goes back a looooooong time, but in later years there is a growing sense of being of one nation. The one thing that unites all Mauretanians is the voice of Dimi (r.i.p.) https://www.youtube.com/watch?v=19aTW5lIygc
Mauretania used to be a godforsaken place that you passed (with difficulty) going to "Africa". It is becoming more and more interesting as its own destination, esp with the troubles now in the rest of the Sahara.