Winter driving france to Spain

Hi there, We are thinking of traveling down to Spain /Murcia for Christmas and was wondering what the conditions of the tollways and A roads in France are like in December/January. We have a motorhome -  a Fiat Ducato conversion. I was thinking of going through France via A16/A71/A75 but noticed on one web site that the A75 was not recommended, in winter.  Does anyone have any experience of this, and/or any other routes.