The four broadcasters were all cut off on Tuesday and Wednesday, the press freedom group said in a statement.
The four broadcasters -- Radio Soleil and TV stations Sikka, Eden and E-tele -- were all cut off on Tuesday and Wednesday, the press freedom group said in a statement.
All were shut down on the grounds that they were transmitting from places away from their original locations, RSF said.
Radio Soleil and Sikka TV are owned by Sebastien Adjavon, a wealthy French-Beninese businessman who ran unsuccessfully in presidential elections in March and was recently arrested on cocaine smuggling allegations.
Adjavon's campaign manager, now an MP, owns Eden, while E-tele backs former president Thomas Boni Yayi, according to RSF.
"The closure of these four media outlets is out of all proportion to the bureaucratic irregularities of which they are accused," said Clea Kahn-Sriber, head of RSF's Africa desk.
"It is hard not to regard these closures as politically-motivated," she added.
"We urge the authorities not to embark on the road of media censorship and harassment, especially as Benin has until now been cited as an example of respect for media freedom."
Businessman Patrice Talon was sworn in as Benin's new president in April, taking over from Boni Yayi, who stepped down after two terms in office.
The vote was hailed as a victory for democracy on a continent where leaders sometimes cling to power for far longer than their constitutional mandate.