Sinha sustained bruises on her neck in the incident.
The incident took place at around 9 PM when the MP from Cooch Behar constituency of West Bengal was coming out of the building.
"Suddenly, two bike-borne men arrived on the spot and stopped next to her. Before Sinha could understand anything, the pillion rider snatched her chain and the duo sped away.
"Sinha's neck was bruised in the incident," said a senior police official.
The MP approached police soon after the incident and a case of snatching was registered.