Originally Posted by davetravels

Oh, yeah! I have assorted sizes of foldable duffle bags - up to 36 inches, and one that's totally scrunchable, that zips up into a little pouch!

True, that this can be a little bit difficult, depending on what city, and how much stuff you have as carry-ons. I have lugged TONS of cr@p around cities, at times, including Paris.

Paris CDG is easy, but it can be a tad expensive, There's a luggage store that has luggage for sale, AND day and overnite storage - and it's DIRECTLY over the RER station where you get the trains into Paris! They actually run your bag thru an x-ray machine before accepting it for storage <as you could imagine> . The shop is called: Bagages Du Monde. Here's a link to their website's left baggage page:

http://www.bagagesdumonde.com/en/left-luggage/offer

Here's a screenshot of their left luggage rates.