In a meeting with a delegation of French lawmakers in Damascus, Assad said France's "mistaken policies... had contributed to the spread of terrorism."
"The terrorist attacks that targeted the French capital Paris cannot be separated from what happened in the Lebanese capital Beirut lately and from what has been happening in Syria for the past five years and in other areas," he said.
Assad was referring to twin bombings claimed by IS which killed 44 people on Thursday in the southern suburbs of Beirut, a stronghold of his Lebanese ally, Shiite militant group Hezbollah.
Assad regards all the rebel groups fighting his forces inside Syria as "terrorists", not just IS.
Assad said he had "warned against what would happen in Europe for the past three years."
Signup to our newsletter and follow us on Facebook and Twitter!
"We said, don't take what is happening in Syria lightly. Unfortunately, European officials did not listen," he said, in comments to the delegation broadcast by France's Europe 1 radio.
He said French President Francois Hollande "should change his policy."
"The question that is being asked throughout France today is, was France's policy over the past five years the right one? The answer is no."
France has been a leading supporter of the Syrian opposition since soon after the outbreak of protests against Assad's rule in 2011.
It is also part of a US-led coalition conducting an air war against IS in both Syria and Iraq.
It has carried out air strikes in Iraq for more than a year but extended them to Syria in September.