If you use a fire extinguisher in a public/business context (in a store, office, restaurant, hotel/B&B...) then it is legally required to indicate the location of a fire extinguisher with a pictogram fire extinguisher hung above the extinguisher. You must also provide evacuation pictograms at each junction and change of direction on the escape route.
The obligation for signage is regulated in the ARAB and the police codexes, among others. These obligations do not apply to private situations.