Whilst it will be cooler this can be an advantage especially travelling around Paris. Further down South and the weather will be milder so if you are going to mix a trip to two areas I would suggest starting in Paris and then moving down South…plus this will also give you the opportunity to relax after the buzz of the city. I loved Paris when I visited earlier this year – I have added some other posts about must sees whilst in Paris – hope these help you as well. Definitely spend time around Notre Dame this will give you a true sense of Parisian life; the Eiffel Tower is a must see but the area is far too touristy and the bars and restaurants are expensive. Hope you have a fantastic time.