The singer from Barbados had earlier posted a photo showing herself at London's St Pancras station — and the time of her train's departure for Paris
marked on a station sign.
She has 25 million followers on her Twitter account.
She arrived at the Gare du Nord in Paris on the Eurostar late on Saturday to find an enthusiastic crowd waiting to greet her.
The station's security team and her own bodyguards struggled to protect her from the crush as she tried to leave the station.
"The French are fuckin insane!!!" she tweeted a little later.
"FYI, if u push me, you WILL get pushed the phuck back!" she added.
"I just had to fight my way out of a damn train station!!!" she exclaimed.
Rihanna later appeared as special guest of British band Coldplay for their sold-out concert in front of 80,000 fans at the Stade de France.