Why is my oil pressure light comming on my peugeot 307 when the car get engine gets warm

You need the transmission fault codes read, but I suspect you will need to rebuild the transmission.

engine oil 20w-40 or equivalent synthetic oil
if the engine has done considerable mileage , could go to 30w -50

You need the engine control computer scanned for both key on engine off and key on engine running.

sounds like engine has seized,because of no oil !!!

Usually that means the oil pressure sensor is become faulty. If your moving on a highway at a a higher continuous speed it is less likely to do it?

sounds like the gearbox selector, by the way have you checked the gearbox oil to see if its low or contaminated

Broken cam belt?
Seized engine?
Does it have oil in it? Perhaps they forgot to refill oil properly?

ck the oil first same answer as before

It could be one of three things. The oil filter has a plastic cross inside that sometimes break and cause this error, or it could be the oil pressure switch. If neither of these solve the problem then it can only be your oil pump. I presume you've checked your oil level before posting.

Does it go off after the car is started? If not, replace the oil sending unit, if it still doesn't go off, have the oil pump checked, the pressure release valve might be stuck.