The 17th and 18th centuries saw the establishment of art academies, both royal and secular, that trained professional artists across europe. in france, the french academy held which established the official style of the time:

 private exhibitions    

Explanation:

             In the 17th century, A Royal Academy of Paintings and Sculptures was established by the French Government under Louis XIV. It was established in the year 1664.

            The academic training at the French Academy was focused on the study of the classical works of antiquity and also Renaissance. It is based in the systematic training of the hand and mind.

            The French Academy organised private exhibitions as well as competitions, which was named the 'Prix de Rome', which reinforced the significance of classical antiquity study and Renaissance masterpieces. These events helped established the official style of the time.

Therefore the answer is --

 private exhibitions  

In France, the French Academy held Private exhibitions which helped established the official style of the time.

Explanation:

Private exhibitions

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