I started noticing that tail lamps in Peugeot 408 are constantly fusing. This may be connected with frequent using of a trunk lid, which is slammed at the close, and incandescent lamps get shaken off. In this case it is advisable to install more reliable lamps, as an alternative, light-emitting diode (LED) lamps; their base is called t10, while bases in incandescent lamps are labelled w5w.
The main difficulty in changing is 16 lug latches; which hold panelling of a trunk lid. They need to be unfastened, but it is very difficult without a special tool (it is shown on a picture) in order to get to the fixture of a flashlight. The back lamp is fastened with two plastic thumb nuts, which are so tightened up that it is practically impossible to turn them off with hands, here it is necessary to use needle nose pliers, which help to hook lug latches on and remove them.
To my opinion, quality LED lamps are much efficient anyway, it is reasonable to change two lamps at once in order to deliver the panel from constantly jerking and provide equal glow of the lamps, as light diodes yet are different a bit in colour, though it depends upon selecting.
When the lamps have been changed, make sure to check that they are alight before positioning the panel.
In the conclusion I want to say though Peugeot 408 is quite an advanced model, it could have been designed on the basis of rich experience of previous models, where this problem was found. But alas, the manufacturer made it even worse, having installed 16 hard-to-remove lug latches that results into a difficulty of changing tail lamps on a trunk lid in Peugeot 308. Perhaps, it is so we are not in clover))