LONDON, Feb 3 (Reuters) - An increase in retail investors flocking to online brokers during the coronavirus pandemic risks creating “bubbles” engineered by social media, France’s top markets regulator said on Wednesday. Robert Ophele, chair of France’s AMF markets watchdog, said the trading frenzy fuelled by posts on the Reddit forum and surge in bitcoin prices have shown how technology and social media can bring “irrationality” to financial markets. “Customers with direct market access are welcome, but raises questions about... new ways to manipulate markets with a social media dimension,” Ophele told an Afore Consulting webinar.