Thilo Kehrer is a defender for Paris Saint-Germain.
There is a two-year option at the London Stadium for the 25-year-old.
Sevilla were interested in signing the 20-cap Germany international, who had entered the final year of his Paris Saint-Germain contract, but he preferred to join West ham.
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After the arrivals of Flynn Downes and Alphonse Areola, Kehrer became the sixth major summer signing. The deal takes the Hammers' spending to more than a hundred million dollars.
He joined Paris Saint-Germain four years ago and has gone on to make 128 appearances for the French club.
He was part of the Germany squad that played in the Nations League this summer.
Kehrer is mostly a centre-back but can also play as a wing-back or a holdingMidfielder.
David Moyes told the club's official website that he was pleased to welcome Thilo to the club.
He can play in a number of defensive positions and add strength and depth to our current options.
I'm very excited to join West Ham United. This is the best league in the world and I'm looking forward to playing in it.
The manager told me how he thinks I will fit in at the club. I want to integrate myself into the group and enjoy playing for West Ham.
Jonathan Johnson is a french football expert.
He is a player that Paris Saint-Germain have been looking to sell. He can play in the middle and also at full-back in Paris.
He needs a run of games to get ready for the World Cup with Germany. He should be able to find a new lease of life away from Paris Saint-Germain.
With a deal in place for Kehrer, West Ham are trying to get a deal done for Emerson.
The clubs are talking about a deal for the left-back, who has two years left on his contract and spent last season on loan at Lyon.
Although Alonso is expected to join Barcelona this month, he is not currently in the running for the left-wing-back position.
West Ham are expected to make an improved offer for Hans Vanaken after Club Brugge rejected their initial offer.
The proposal from the Hammers was thought to be around 10m.
The transfer window will close at 11pm on September 1st.
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