Tamil Nadu Police arrested opposition leader Udhayanidhi Stalin in Chennai on 4 August.
The arrest followed allegations concerning remarks he was accused of making about Chief Minister Vijay and actor Trisha Krishnan.
The remarks were characterised as derogatory or sexually suggestive in the allegations described by political opponents.
The allegation concerned comments at a public meeting on 3 August, held amid debate over the Cauvery river water-sharing dispute.
The account of that meeting said audience members invoked Trisha Krishnan's name while Stalin was criticising Vijay over the Cauvery issue.
It alleged that Stalin then made an ambiguous, suggestive comment.
TVK said the detention was not an act of political retaliation and was prompted by alleged inappropriate comments about women.
TVK leader Aadhav Arjuna accused Stalin of insulting women and damaging the quality of political discourse.
Additional police were deployed outside Stalin's residence in Chennai, the account said.
The same account said Stalin had sought anticipatory bail from the Madras High Court before his detention.
The evidence set does not establish the exact wording of the alleged remarks, the charges filed, or the outcome of any court proceeding.