PARIS — Nicolas Sarkozy, the former president of France, went before a judge Thursday to respond to allegations that he illegally accepted donations from France’s richest woman to fund his 2007 election campaign.

The judge could decide whether Sarkozy, a polarizing figure who often faced criticism for cozy ties to the rich, will be charged with taking advantage of heiress Liliane Bettencourt, 90. Sarkozy has consistently denied all allegations.