If it is plain paper stuck to the negative, just soak in water for about 1/2 hour and gently peel or rub the paper away taking care not to scratch the negative by over eager rubbing. Then dip the negative in photo flo or something similar and dry.
If it is before processing, and the paper backing is stuck, process as normal and then in the wash follow the procedure in the above paragraph. The paper should peel away slowly and easily. If it is stuck on the emulsion side, the negatives will likely be ruined though due to uneven development.
PE