1hr is sufficient in most cases but you must be quick. Your gate will provided before landing (Air Nostrum flights normally depart from gates K86 to K93 in the far north side of the main T4 terminal). If you see an IB rep at the arrival gate let him know you’re there so that the guys at the Paris gate know you’ll be able to make it on time.

First you’ll have to go by the passport control (cut politely the line if necessary) to get out of T4S via monorail (use the lifts as they are quicker) then look for the K signs and run to your gate. If your flight is delayed you’ll find the IB lounge in the middle of the terminal (one level above the main concourse).