You haven’t told us what type of car you have or what age.Is it a diesel because if so then yes if you are not doing many miles then there is a chance you are not clearing the DPF in the exhaust,this an issue with all modern diesel cars not just Peugeot’s
Have a look at my post regarding diesels with AdBlue and what you might expect regarding possible NOX sensor warnings. If your light is intermittent then yes a good run once every couple of weeks or so will help. I don't know your car, but if it has a Diesel Particulate Filter (DPF) it needs a good run to heat it up which will burn off the contaminates collected by the filter and keep it clean. This maybe the cause of the warning light intermittency. The NOX sensor controls the injection of Urea (AdBlue) into the exhaust system to reduce emissions too. We have two diesels of 2016 vintage and we have replaced both NOX filters this year, seems they have a life mileage of around 40-45K.
My post "NOX Sensor Part 2 - Peugeot 2008 GT Line 1.6 BlueHDI" is in the Technical forum.
pottering about in a modern diesel isn't good for them, I do quite a few drives where the engine doesn't even warm up but I do manage to do at least 1 longer trip every week, havn't had a problem yet (probably jinxed it now)