Real have already sealed deals for Eder Militao, Luka Jovic and Eden Hazard for a combined outlay of up to €270m once reported add-ons for Hazard are counted. Lyon's Ferland Mendy is also believed to be close to a €50m transfer, but midfield is an area that still needs strengthening.
Pogba has been heavily linked with Real ever since fellow countryman Zinedine Zidane returned to the Bernabeu earlier this year. But with the general consensus that Manchester United would be unwilling to sell the 2018 World Cup winner, Real could turn their attention elsewhere.
Eriksen is also a rumoured target, but El Partizado de COPE suggests that Ndombele could become a serious target if neither the Dane nor Pogba look like they will sign.
Ndombele is still only 22 years old, but the young Frenchman has emerged as one of Europe's most talked about new talents in the last couple of seasons.
Ndombele, who made his senior international debut for France last October - replacing Pogba in a friendly against Iceland, is currently under contract at Lyon until 2023. It gives the French club a strong negotiating position to demand a potentially enormous transfer fee.