This was before a whole series of terror attacks in Europe and elsewhere in 2015 and on, but still wild.
https://www.newsweek.com/16-french-citizens-support-isis-poll-finds-266795
One in six French citizens sympathises with the Islamist militant group ISIS, also known as Islamic State, a poll released this week found.
The poll of European attitudes towards the group, carried out by ICM for Russian news agency Rossiya Segodnya, revealed that 16% of French citizens have a positive opinion of ISIS. This percentage increases among younger respondents, spiking at 27% for those aged 18-24.
A recent Ifop poll placed French president Francois Hollande's approval rating at just 18%.
The survey also tested attitudes in Britain and Germany and found that 7% of British citizens responded favourably to ISIS. However, UK polling showed an inverse demographic trend to that of France, with support for ISIS rising with age. 4% of 18-24-year-olds saying they either strongly or somewhat support ISIS, compared to 6% of 24-35-year-olds surveyed and 11% of 35-44-year-olds. Positive attitudes to ISIS in Germany showed less divergence, remaining between 3% and 4% for all age groups.
2014 but feels like ancient history
but why would they support ISIS
did people ideologically identify with them
Yes. 2014 was peak ISIS strength too. France has a big Muslim population, so that's also why. But also. We're not really allowed to ask the question "What does ISIS want?" So they're just like every other Disney villain, doing bad things because their souls are rotten or something. But the history is more complex than that and you can't have such big support built on pure irrationality.
Their methods are obviously terrorist, and that's their biggest problem, so I'm not defending anyone here. But here's the very gist of it: ISIS wants a restoration of the Ottoman Empire, which joined WWI on the side of the Axis and then was "Balkanized" by the Allies in the aftermath. So basically a powerful nation was cut with a ruler into a bunch of weak colonial states that never existed before. Just from that, you get a powerful cultural impetus to restore the former glory, to make the decadent West pay for the humiliation, the hate of Israel, but also of more moderate (shia) factions of Islam.
So on the religious front, ISIS favors a very literal interpretation of Koran, selective too, and consider other interpretations and interpreters their enemies too. Not a good way to make friends all around. Plus, ISIS has a strong propaganda effort. US helped a lot forming the movement by doing what they did in Iraq, Libya, Syria etc. To say nothing, again, about what Europeans did in the region before and together with the US after. ISIS minister of economy, if I'm not mistaken, is (was?) an Australian banker. They recruit widely, it's not just those deranged people cutting people's heads in videos. Many former army personnel that got defeated by the US in Iraq in 2003 is (was?) ISIS. Aleppo showed that they are good at war, they're not dilettantes with machetes. This must be attractive to a certain type of person too. All that is to say: yes, there are people who ideologically identify. Much much less now, obviously, but this won't go away easily because at the root of the movement is a historical humiliation.
The following year was the Charlie Hebdo terror attack and the year after that was the Bastille Day attack in Nice
France ghettoized African and Middle Eastern refugees at the local level, refused to even take racial data into account when making policies at the national level, and the French liberals then watch with mouth agape as the right wing and Islamic terrorism in France rises up as the liberals do nothing.
French liberals love to act like they don't have racial problems like Americans and then proceed to blame any form of racism in their society as if it was being stirred up by American culture or just ignore it altogether.
...but France is 5% Muslim (8% among under 30s)
And even then I highly doubt that even in most chud (but still not outright lies) estimates, more than a quarter of them would support such groups