It is not June 1830 ,it is July 1830.
Where is this written in NCERT??
This statement was given by an austrian Chancellor Duke Matternich. In June 1830 there was revolution done by liberals in france and ended by the establishment of a constitutional monarchy with louis phillepe. This encouraged other countries of Europe. On this matternich stated this comment

During the \’Age of Revolution\’, the first insurrection took place in France in July 1830. The Bourbon dynasty, restored during the conservative reaction after 1815, was overthrown by liberal revolutionaries. In its place, a constitutional moarchy with Louis Philippe at is head was installed. This \’July Revolution\’ led to another insurrection in Brussels and led to Begium becoming independent from the control of the Kingdom of Netherlands. Even before these events, it had been witnessed that France was the political nervecentre of the rest of Europe. Ever since the French Revolution, the political developments in France had direct impact on the rest of the European continent. Hence Metternich said \’When France sneezes, the rest of Europe catches cold\’.

What Metternich means by this quote is that if whatever happens to France, the rest of Europe will feel the effect as well. This is do to the fact that France is one of the main powers in Europe and holds many points of influence. At this time in history, France is also the most powerful nation. The French courts were held to a high standard and French was the main language everybody learned in Europe

During the \’Age of Revolution\’, the first insurrection took place in France in July 1830. The Bourbon dynasty, restored during the conservative reaction after 1815, was overthrown by liberal revolutionaries. In its place, a constitutional moarchy with Louis Philippe at is head was installed. This \’July Revolution\’ led to another insurrection in Brussels and led to Begium becoming independent from the control of the Kingdom of Netherlands. Even before these events, it had been witnessed that France was the political nervecentre of the rest of Europe. Ever since the French Revolution, the political developments in France had direct impact on the rest of the European continent. Hence Metternich said \’When France sneezes, the rest of Europe catches cold\’.