Forex change- cheapest fees?

Where is the cheapest place to change forex. 

Lowest fees and best rate?

Is the ATM where you insert € and get Rupee best?

In Riviere Noire area - but generally anywhere is ok.

Thanks.

I don't think you can insert forex into an ATM and get Mauritian Rupees in exchange.

Your best bet is to visit the websites of the main Mauritian banks and check their fees for forex.