People who refuse a marriage proposal in Mangalmé in north-eastern Chad must now pay a fine, known as “amchilini”.
The region’s Higher Islamic Council ruled that the figure be between $23 (£18) and $39 for women and $15 for men.
The Chadian Women’s Rights League has launched the hashtag #StopAmchilini to denounce the decision, saying it is illegal as it violates a national law guaranteeing freedom of consent to marriage.
The Islamic Council says its decision was inspired by the Quran. Forced marriages are prevalent in Chad, with young under-age girls the usual victims.
Despite a law passed in 2015 that prohibits child marriages, 60 percent of women aged between 20 and 24 were married when they were still children, according to figures from Chad’s Institute of Statistics.