I did my own ad hoc planning and to be honest turned out massively difficult as I did Calais Paris as thats the way I have always driven , It was still great but last year got caught in Monsoon weather from Abbeville and can tell you it was not fun.
I came across this and apparently most charitys use this route or near to it and seems a lot more sensible to what I have been doing I am planning to do this route exactly this year even maybe try it in one day. http://www.donaldhirsch.com/dieppeparis.pdf.
This route seems to have bike friendly hotels etc which in my case usually turns out very expensive I paid £150 last year for a night as it was the only one who said bike friendly, or out of the way by miles, something you want to avoid doing more miles than necessary.
I also once took too much kit with me considering I was staying in hotels problem with panniers is they slow you down on flats and their inclines are long and even longer.
I now have a small backpack and find that suits me fine and much more comfortable.
Please note you need by law in France to have a Hi Vis and lights otherwise they fine you upto €350.
Paris is mainly cobble stone so again dont do what I do and have slick 23c tyres .
Please do let me kow if there is anything wlse I can help with.