The Belgium international has been linked with PSG - with reports in France suggesting the Argentine striker Ezequiel Lavezzi could move the other way in part-exchange.
"For now my mind is 100 per cent focused on Zenit," Witsel told Belgian daily Sudinfo.
"PSG are one of the clubs who no player could be indifferent to. You could not refuse that."
Laurent Blanc is set to replace Carlo Ancelotti as PSG coach and Witsel is in the dark as to whether the former Bordeaux and France coach would be interested in signing him.
"Does Laurent Blanc like me? I do not know anything," he said. "All I know of him is his sporting career.
"In football, everything can happen quickly. But I cannot say any more about it, because I do not hold any of the cards."
Witsel, 24, scored four times in 19 appearances for Zenit last season following a big-money move from Portuguese side Benfica.