Several different sectors of employees will be striking -- so much so that the civil aviation authority went ahead and asked airlines to cut their schedules in advance -- about a quarter of flights will be cancelled at CDG tomorrow.
In addition, expect delays getting through check-in and security and immigration.
Just even getting to the airport can be difficult too, especially on the road (via taxi or Uber), because often during these strikes, the strikers also protest by blocking vehicular traffic on its way to the terminals -- people often end up having to walk. So if possible, it's better to take the RER -- and RER / Orlyval for Orly.