t = [ {'id':1, 'age':23, 'sejour':'PEKIN'},{'id':2,
    'age':27, 'sejour':'ISTANBUL'},{'id':3, 'age':53,
    'sejour':'LONDRES'},{'id':4, 'age':41,
    'sejour':'ISTANBUL'},{'id':5, 'age':62,
    'sejour':'RIO'},{'id':6, 'age':28, 'sejour':'ALGER'}]

r = [ c for c in t if c['age']>30 and
    c['sejour']=='ISTANBUL' ]