Police investigating the stabbing of a French soldier in Paris arrested a suspect on Wednesday morning which sources described as an adherent of "radical Islam".

"The suspected perpetrator of the attack on a soldier Saturday evening in La Defense (business district) was arrested this morning," Interior Minister Manuel Valls said in a statement.

The statement said the suspect was arrested in the Yvelines district on the western outskirts of Paris.

Sources close to the investigation said the 22-year-old man has been a follower of a "traditionalist even radical Islam for the last three or four years".

But the sources urged caution in a case that is still in its early stages, saying the suspect was not known to be a jihadist .