Horizontal tug from steering at 70kph+

Hi. When i drive my car over about 65 or 70 kph i sometimes feel a tug of the car to the side right or left, like it wants to slip perpendicular to the direction of motion. It's a little worrisome, I don't think I've experienced it before.

Car is 2005 Renault Megane 2, AT. Car passed inspection three months ago.

Any ideas what could be wrong? Thanks for the help