July 27 (Reuters) - Spain's real estate group Inmobiliaria Colonial posted on Thursday a net loss of 347 million euros ($381.53 million) during the first half of 2023, hit by a downward revision of the value of its assets.

The group, whose portfolio comprises office buildings located in Spain and in Paris, swung to the red from a year-ago profit of 355 million euros, but reaffirmed its full-year guidance projected in February, expecting earnings per share of between 0.28 and 0.30 euros.

The main business of real estate investment companies such as Colonial and its peer Merlin Properties is the rental of its assets, but they have to include in their results the impact of an updated valuation of their properties every six months.

Central banks' monetary policy tightening has put the real estate sector under pressure since the second half of last year, slowing down investments in properties. ($1 = 0.9095 euros) (Reporting by Matteo Allievi, editing by Andrey Khalip)