Nouakchott is still developing, with many small, local businesses and a mostly cash based economy. There are many subsistence farms on the outskirts of town, and many residents live on very modest incomes.
A few of the country's banking institutions are set in Nouakchott, as well as head offices for Mauritania Airlines and a couple of other major businesses. There are often jobs in mining around the Nouakchott area, with rich phosphate mines that can bring in foreign jobs, and iron as one of the country's main exports.
Some expats come over to teach, and if you have fluent French skills you may be able to find work in Nouakchott, with a few jobs for teaching English as a foreign language. You'll also find there are a few medical jobs in the area, mostly for those with western qualifications who can provide healthcare for foreigners living in Nouakchott.
As you might expect, salaries are not particularly high, although the cost of living is very cheap, with Mauritania being one of the countries with the lowest cost of living in the world.
Those planning on working in Nouakchott will need to secure a job before they arrive, and a requirement of a business visa is having an invitation from an organization within Mauritania to confirm that you will be working for them, or undertaking business in the country.
Once you've got confirmation in writing, you can apply for a visa through your local embassy, usually through the mail, although for longer visas they will sometimes call you in for an interview to discuss your situation. Visas aren't available at the border or on arrival.
You should register with your local embassy when you arrive for security reasons, and they will be able to help you with renewing your visa when the time comes.
If you work in Nouakchott, you'll be considered under resident tax rules if you reside primarily in the country, own or rent a home, and earn most of your income from the job there. This means that you'll be taxed on income earned in Mauritania, as well as abroad, unless you can prove that the income has already been taxed in the source country. Under double taxation rules, this income wouldn't be liable for further taxes. Mauritania has double tax treaties with France, Senegal and Arab Maghreb Union countries.
Personal income taxation is progressive, with rates as follows:
If you're making income from investments or rentals, dividends and interest are taxed at 10% and capital gains at 25%.