There will be fence on Finland - Russia border, just like the one pictured in here

200 km of new fence is about to finish by late october

https://www.verkkouutiset.fi/a/esteaitaa-rakennetaan-itarajalle-yhteensa-200-kilometria/

There are 400 people building it.

Every 3 kilometers there is a kamera monitoring the situation.

It is unlikely Russians will climb up this fence.

The border in Lapland is however not going to be fenced. Nobody likely tries to come through it anyway, in winter its -30 degrees and everywhere is nothing but wilderness and bears.