Why is it called a flea market?

it come from the DS game called animal crossing: wild world

HA......hardly, this is the answer I found many times over:

Flea markets, where secondhand goods can be had cheaply, are not just an American phenomenon. In fact, the word "flea market'' has its origins in the name of a famous Parisian street market.

The "Marche aux puces Saint-Ouen'' is a colorful market on the northern border of Paris that is a favorite stop for tourists and locals alike. In the winding alleyways that make up the Marche shoppers can hone their haggling skills and perhaps find a rarity among the booths and tables. The Marche aux puces has been in operation for more than a century.

Francophones know that the French phrase "marche aux puces'' literally translates to "flea market.'' George Dougherty wrote in his 1922 book In Europe that the Marche aux puces "is called the 'Flea' Market because there are so many second hand articles sold of all kinds that they are believed to gather fleas.''

Whether Doughtery was merely parroting Parisian folklore or relating the actual etymology behind the French name, his use of "flea market'' to describe the street market is the first known example of this term in English. The term didn't begin popping up with any real frequency until the 1950s. At that time, it was usually used to refer to markets of this type in Paris, Spain and elsewhere in Europe. During the 1960s, however, it began to be applied more frequently to such gatherings in the United States.