Unless you're traveling in First class or are a SEN or higher(assuming you're flying on LH) I believe the only access you'll have is to the paid storage centers outside of security.
From another post on FT about lockers for a 21" bag in the SEN lounge of the B gates: "it seems there are apx 30 lockers with keys that will fit a 21" roller board, so they each took a locker and saved having to pay Left Luggage anything, Just they had to leave a CC or drivers license as security till the key is returned to the front desk. I guess anything more then 1 piece and either just leave it somewhere or pay that luggage room you mentioned."