Travelling before a visa starts

I obtain a six-month temporary visa each year to visit our second home in France but usually like to come a few weeks before it starts. Will I need EES/Etias? 

You will likely need both, yes, as you will be entering without a valid visa at the time of entry. 

We would advise drawing the border guard’s attention to your plans – we expect it will be possible for them to note in the database the dates of your visa so you are not flagged up as ‘overstaying’ when you return.