Police arrested Nebojisa Medojevic, an MP from the opposition Democratic Front, and sent him to jail in the capital Podgorica on Friday to serve a two-month sentence.
He had been convicted of refusing to testify against the former long-term mayor of Podgorica, Miomir Mugosa, in a case involving corruption and misuse of office allegations.
Montenegro's ruling DPS party wants its leader Milo Djukanovic to be a candidate in the presidential elections in 2018.
The Podgorica-based daily Pobjeda writes that the DPS main board will meet to consider this by the end of the month - and that the mood "at all party levels" is "unanimously" in favor of Djukanovic running.
A new regulation adopted by the Montenegrin parliament, after recent violence between opposition and majority MPs, envisages harsh fines for lawmakers who brawl inside the parliamentary chamber.
The new rule is to be implemented by parliament from its autumn session, which is due to start in September.