This is a kitchen shop, advertising that it's got a crazy sale going on. Dingues translates to crazy, and is pronounced dahng. (Think "dang" with a Texas accent.)
I think it would have been fun to watch this photo shoot as a fly on the wall. "We promise, ma'am, when we're all done, if you do a good job, we'll let you do one serious shot."
The French sales run twice per year and are on set dates, depending on the department. In ours, the Seine et Marne, winter sales began January 11 and run through February 14. Summer sales will be from June 27 to July 31 this year. They've been ongoing for two weeks and I still haven't really gotten out there for this round of deep discounts.
I pass this girl daily on my street, so I won't forget before the time is up. There are usually some good deals to be had.... I'd be dingues not to go and at least look.