After searching the flight and its passengers, police said the alert was a false alarm.
A British Airways flight was held at Paris airport following a 'security threat', reports claimed.
Terminal 2 at Charles de Gaulle International Airport in Roissy.
'The pilot then said there had been a direct security threat involving our flight specifically.
All passengers were later given the all clear and British Airways has informed them they will be able to travel on a replacement flight later on Sunday.
Flight BA303 was due to take off 7:25 a.m. Sunday bound for Heathrow in London when the incident occurred.
He said: "Everybody's been individually searched by armed officers and given all clear".
Passengers waited on the tarmac near Terminal 2 as security personnel and sniffer dogs searched bags and aircraft. That's when we noticed police and fire vehicles quickly surround the plane and dozens of armed officers and firefighters got out. They're being extremely thorough and we're being escorted by armed officers'.
Around three hours after its scheduled departure, at 11.10am, a BA spokeswoman confirmed the flight had taken off.
An improvised explosive device partially detonated on a train at the Parsons Green station on the District line, injuring 29 people.
Intelligence chiefs raised the threat level to "critical" meaning that a second attack could be imminent.
An 18-year-old man was arrested in Dover on Saturday in connection with the attack.