I have been in and out of Nice airport with tons of gear and no duties, taxes or VAT issues. I came to France with two Gavins and a ton of OC gear in baggage. Then Rubis brought over my Zeuxo scooter last year, no issues, it was still in the shipping box. Keep a low profile and say you are on holiday.
Hawaiian print duffel bags scream tourist.
I have had two gear issues at Cote d'Azur. Security told me I had to check my lead acid batteries that were in my carry on when we went to Scapa. When I left France I got called to the flight line to open a bag. Some reason four second stages with brass air barrels inside a Halcyon pro-14 look like four hand grenades on X-ray.
Bonne Chance!!!
Kevin