reflux
This reflux is a worry for security service in France and across the continent,precisely because newly expert and inflamed ,the returnees can perpetrate commando-style attacks like that on Charlie Hebdo ]
1From the economist
2"reflux"?
3 {newly expert and inflamed }?

Question

reflux
This reflux is a worry for security service in France and across the continent,precisely because newly expert and inflamed ,the returnees can perpetrate commando-style attacks like that on Charlie Hebdo ]
1From  the economist 
2"reflux"?
3    {newly expert and inflamed }?

Answer

"Reflux" here means "the return to what happened before in history".

"Newly expert and inflamed" mean recently the group thinks they are right and are again excited and trying to put their beliefs into action.