Public transport in Paris is really easy to get used to. It operates just like any other western city in the world. You may automatically think of the Metro system when you consider France, but the RER is another option that people tend to go for.
The RET has been working ever since 1961, and has stops in Paris. Some of the city’s suburban areas also have stops, too, meaning that it’s really easy to get around in the French capital city. Some stops are even shared with the city’s Metro system, which is also a useful way of getting around.
Tickets for both of these rail systems can be used interchangeably, and tickets generally don’t cost that much. You should expect the trains to be running roughly between 5:15am and 12.30am every day – so there are only a couple of hours during the day that you would have to rely on taxis to get around.