What is a "fiche" and do I need one for Mauritania?

It is not obligatory but helpful to carry fiches in Mauritania.

A fiche is a piece of paper that does not follow any specific format and provides mostly passport and visa information. When traveling overland in Mauritania or the Western Sahara one encounters many police checkpoints where such a paper can minimize waiting time, as the officer usually will skip any questions and let you carry on and use the paper slip to record your transit.

A simple copy of your passport photo page and one of the Mauritania visa will also suffice. The most important question that would not be answered by it is your occupation.

Also at the train station of Nouadhibou we were asked for one. My travel mate did not have fiches but it did not slow us down noticeable. You can offer a number of fiches to the driver of your bus or tour guide on departure which helps. On my route from Nouadhibou-Choum-Atar region-Nouakschott-Rosso I handed out less than 10.

I printed the information 6 times per DinA4 page beforehand and then manually wrote the number and dates of my Mauritanian visa in it once I had crossed the border. Though one could easily print it only in Mauritania too.

The fiche I used had following info in French:

Prenom:
Nom de familie: 
Nationalite: 
Date de naissance:  
Lieu de naissance: 
Numéro de passeport: 
Passeport valide de ... a ...
Passport delivre a: 
Domicile:
Profession:
Motif de voyage: Tourisme
La date d'entrer à la Mauritanie:
La date prévue pour quitter la Mauritanie:                                      
Route: Dakhla, Morocco – Nouadhibou – Atar – Nouakschott – Rosso – Dakar, Senegal
Visa Mauritania: (number, issuing border post number and start/end dates)