About entry in Europe [duplicate]

As for passing immigration control in Frankfurt, that is completely fine. You would do that anyway if you were flying to Paris, because the Schengen-internal flight to Paris leaves from the "domestic" side of the border controls in Frankfurt.

In some places on the net you can find written that you need to have an onward flight towards the country that issued your visa, but that is an oversimplification: Any reasonable arrangement for onward transportation to your main destination country will do, land or air does not matter.

However, if you plan to do this, you need to change your flight ticket be for Frankfurt only. This may cost you (possibly large) change fees, but is inescapable. Airlines are notoriously unhappy about passengers leaving an itinerary in the middle (because they often charge more for a direct flight to Frankfurt than for a connection through Frankfurt).

Without changing tickets, you will have problems getting your bags in Frankfurt (they will be transferred to the Paris flight automatically -- you won't see them for customs purposes, because you would clear customs on arrival in Paris). And even if you travel without hold luggage, the airline will probably cancel BOTH legs of your return flight without any refund after you abscond from the connecting flight in Frankfurt.