All western countries maintain good relations with Mauritania. The only sanctions against the Mauritanian government are denunciations by UN special rapporteurs respecting extreme poverty, human rights, racism, xenophobia, slavery, and torture. The rapporteurs prepare strongly worded statements and documents that annoy the Mauritanian government, but other countries unfortunately have not yet gone beyond statements of principle to impose sanctions.
On June 12th, 2017. See this statement in context.