Louis has been linked with a £1.7m move to the Scottish champions but it seems likely that they will be outbid by Standard.
The Belgians have embarked on an ambitious recruitment drive this summer which has already involved the £1.3m fee paid to Celtic for Tony Watt. They are now expected to add Louis, a Haitian midfielder who scored 12 times for Nice last season.
Losing him is likely to trouble Ronny Deila much more than the departure of Watt, whom the Celtic manager criticised before selling the 20-year-old to Standard. However, Watt's new coach has insisted that he is quite satisfied with the Scot.
"I don't care about his past, only his future," said Guy Luzon, the Standard coach. "I love his talent and the way he plays."