Because the incident comes just days before the election, it could lead to "a greater performance of Marine Le Pen than otherwise would have been the case," Fredrik Erixon, director at the European Centre for International Political Economy, a Brussels-based think tank, told CNBC.
Leader of the right-wing Front National party, Le Pen has campaigned strongly on security and called for an outright halt on immigration as a means to prevent radicalized individuals from entering Europe. The politician, who has been liked to President Donald Trump, said in a recent speech that mass immigration enabled terrorism.
"It's difficult to see how this attack will not play into the hands of political forces that want this campaign to be focused only on issues around migration and terrorism," said Erixon.
An Elabe poll conducted earlier this week showed centrist candidate Emmanuel Macron was set to clinch Sunday's vote, but Thursday's shooting could now put Le Pen in the lead.
"The Paris gunman attack may well swing support in her favor; and this may not be picked up by the polls in a timely manner," said Vishnu Varathan, senior economist at Mizuho Bank, in a note.
France has been in a state of emergency since 2015 due to numerous attacks that have killed more than 230 people in the past two years, according to Reuters.
The Paris attack will get voters thinking on which candidate is best able to tackle the nation's terror crisis, said Simon Tormey, head of the school of social and political sciences at the University of Sydney.