France plays catch-up coping with radicalized prisoners

Radicalized inmates in the general prison population can quickly start influencing others and endanger prison staff. It's a problem that has dogged French authorities for years and is set to grow more acute as foreign fighters return to France amid the collapse of the Islamic State group.

More citizens from France have traveled to the battlefields of Syria and Iraq than from any other European country, and the United States is urging allied nations to claim their nationals held by the U.S.-backed Syrian Democratic Forces because facilities there are filling up.

Making room for more returnees in French prisons, some built in the 19th century, could put new strains on the prison system — and be a tight squeeze. By December 2017, some prisons were over capacity by 220 percent, according to the Justice Ministry.