Third-state people which was a social structure of society in the European peninsula were mixed of two classes of people based on their economic standards one was middle-class people and the other was lower-class people I.e workers and farmers. After the American independence and the French revolution, which was the struggle of middle-class people against the established old institution of the state. Middle-class people were able to put the monarch behind the curtains and came into the frontline in utilizing the power. 

American independence give the concepts of fundamental rights of the citizens, and people were given a sovereign power, which could not widespread because it was on the other side of the sea. But this role was portrayed by the French as a revolution that brought the wind of changes to the doorsteps in Europe.

French Revolution gave birth to new concepts like the right to private property, human and civil differences, constitutional monarchy, secularism, individualism, and Nationality. This was the process of the transition of the state center from old institutions like aristocracy, monarchy, and feudal to the common people. And when we say common people, there stand middle-class people and working class, people.

Due to the economic vulnerability of working-class people they were unable to share the opportunities of sharing the national power, therefore whole benefits were taken by the middle-class people. This is why, in 1797, the Constitution promulgated in French incorporated a right to franchise only to the people holding private property. Women, too we're deprived of this.

Middle-class people counted their heads with working-class people to fight against the state and when they came into power they exploited the working-class people and available resources of the state. This is visible in the industrial revolution par. The lower-class people were so exploited that their life expectancy reached 17 years which drag the concentration of Karl Marx who spoke for the collation voices of workers around the globe, giving both to communism.

Communist was always in favor of the working-class people this is always opposed by middle-class people because they don't want to share the resources with others being equal in stakeholding, this is why the US calls itself a policeman of the world makes a call that communism breaches the price of the world peace. The reason lies here. 

Back to the topic, as there was no pressure the middle-class people developed to their optimum till the start of the world war.

The slogan of the French revolution liberty, equality, and fraternity was the foundation of the emergence of middle-class people who developed as 

Liberty 

Liberty or freedom from the burdens of the feudal, aristocracy, feudal, and the universal church paved the avenue of personal development. People became innovative, and new means and modes were invented. It gave a way to the machinery world. This is how individualism emerged.

Equality 

Equality was all about equal opportunities, for all. This played as the time of catalyst for the industrial revolution, where individualism appeared from liberty converged with equality to initiate the industrial revolution.

Industrial revolution 

The industrial revolution displaced the old mercantile system producing more final products. With the increase in the production rate now the state which was under the control of middle-class people set off on the journey for the new markets. 

The journey of colonialism which was in search of natural resources now changed the direction of the wind. There started a conflict between superpowers. There was three nature of conflicts :

1) Conflicts in the seaways 

2) Conflicts on land routes 

3) Capturing markets 

This was the main reason for the rivalry between superpowers which will be settled in the world war.

This is why the world war happened with the imbalance in the power equation.

Fraternity 

Fraternity played a significant role in bringing Germany to power. Before the French revolution, German was divided into four States, and in every state, people were of the same origin. When the wind of fraternity came to the surface, Bismark inaugurated efforts in qualification, and by the end of 19 century, German was unified, which was the emergence of new power. 

Not on this, but the Russian people and Serbian were united emotionally, and the ottoman empire was struggling against the new coming powers and Britain who declared them as a ruler of the world where the sun never sets, in such a milieu Germany came to ask it's a stake in the whole world. Which was one of the causes of the world war. The fraternity was the agenda of the French revolution which gave dragged the world into the world war.

History is interlinked between the present world and the past world.  The significant slogan of the French revolution which gave birth to the emergence of middle-class people to power was allegedly preparing for the world war.