Good afternoon andd thank you very much for your question.
This warning is caused by the battery in your key remote that is beginning to give low output and needs to be changed soon.
You do not need to go to a Peugeot dealer for this, or any garage for that matter. You should be able to obtain a battery from any electronics shop or even a store such as Timsons. Once you change out the battery, you may have to reprogram the remote.207 PLIP PROGRAMMING 1. Turn the Ignition switch to the ON position using the first key.2. Press the LOCK button for 10 seconds.3. Remove the key and wait for 10 seconds.4. Check the Plip key operation.5. Repeat for second Plip key if required.6. Turn the ignition OFF
I hope this answers your question, but if you need any further help, please reply to this answer.