My passport and UK BRP was stolen in Paris. I have recieved my new passport and new visa to enter into UK has also been issued. Additionally I have french police complaint and also the copy of the schengen visa on which I entered in Paris. I want to travel back to UK with documents on Eurostar. Will eurostar allow me to travel with these documents?

I would contact Eurostar and ask them, as well as the relevant UK government agency (https://www.gov.uk/browse/visas-immi...ving-in-the-uk).

I imagine Eurostar only cares that you have a valid ticket and valid ID, but I could be wrong.

UK Immigration officials are another story.

It isn't "Eurostar" that decides but the UK immigration authorities present at Gare du Nord after Eurostar check-in.

The Eurostar checkin process at Paris doesn't, unless you go out of your way to find a human being, involve anyone checking anything. You just feed your ticket into a machine, then join the queue for UK immigration.

The usual airline obsession that the airline might be fined for carrying an illegal migrant doesn't apply in this case. The UK immigration people determine who gets on board: not the carrier.