The move by France's banking and insurance regulators aims to enable companies currently located in Britain to go on operating freely across the European single market.
London's financial district has benefited from Britain's EU membership as it gave British and non-EU banks operating there access to the entire single market.
Frankfurt and Dublin have already gone on a charm offensive following the shock June Brexit vote to woo London-based financial institutions.
As an EU member, British-based firms have so-called passporting rights, which allow them to do business across the 28-nation EU and the 31-strong European Economic Area, which includes Iceland, Liechtenstein and Norway.
But Britain's departure from the bloc could strip companies of those rights, which are expected to be one of the key issues in the negotiations on the terms of Brexit and are expected to take around two years.
The country's financial watchdog said this month that 5,500 British-based financial firms could lose their EU passporting rights, posing a significant risk to the finance sector.
The French authorities hope to woo firms with a simpler and quicker approvals process.
It would include using available documentation in English that has already been presented to the original regulatory authorities, French regulators said.
"Applicant establishments will be assigned an English-speaking case manager, who will guide the procedure" and advise them, they said.
The ACPR banking insurance watchdog has also set up a Brexit online mailbox for queries and forms.
Earlierthis week presidential candidate Nicolas Sarkozy vowed to offer the UK and exit from Brexit if he is elected to the ELysée Palace next May.
Sarkozy said if elected he would draw up a new European treaty that would be more favourable to British interests in a bid to persuade the UK to stay.