all saints day
traditionally, halloween has never been celebrated in france, and only recently have the french taken on this american tradition.
however, a national holiday that is very much observed by the french is actually related to halloween and is celebrated the day after (1st november). la toussaint, meaning all saints' day, is a catholic holiday and all schools and banks are typically closed. la toussaint is a day that commemorates people who have died.
traditionally, november 1st (all saints' day) would honour public figures who had died, whilst november 2nd (all souls' day) would honour friends and close relatives who had died. as la toussaint is a day off, families traditionally combine these two days of remembrance into one.
the tradition of laying chrysanthemums on graves for all saints' day began following world war 1, when the president requested on the first anniversary of the end of the war, that soldiers who had died fighting for their country be commemorated by laying flowers on their graves. chrysanthemums were the only flowers available at that time of year, and so became part of the tradition.
walking around the streets of france at this time of year, you can usually see chrysanthemums being sold in stores, florists and local nurseries in abundance.