West Ham have bid around £17 million including add-ons for Monaco midfielder Soungoutou Magassa.
France U21 international Magassa was the subject of an offer from Nottingham Forest earlier in the window.
The versatile 21-year-old plays predominantly as a holding midfielder but can also operate in a box-to-box role and as a centre back.
Magassa started 16 games for Monaco last season and also featured in the Champions League, gaining valuable experience against elite European opposition.
He was part of France’s squad at the Paris Olympics last summer, coming off the bench in the final as Les Bleus were beaten 5-3 by Spain after extra-time at the Parc des Princes.