In my country they have a ceremony called 'Khatam' al-Qur'an whereby each of us is given say three chapters (Juzu'e) to read at home, then we will have a final ceremony where we will read the last Juzu'e together. Is this an innovation?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.On the way in which you have asked, there is no supporting evidence in Sunnah, nor is there any record on the deeds of our previous virtuous predecessors. The best way for a Muslim is to read the Qur'an alone by himself, and invoke after completion. There is no harm if he calls his family during invocation as recorded in al-Darami Sunan (book), as narrated by Thabit al-Bunani that Anas bin Malik (Radiya Allahu Anhu) used to call his children and family for invocation after completion of Qur'an reading. Sheikh Hussain Assad confirmed the soundness of this narration. Sheikh al-Islam Ibn Taymiyah (May Allah bless him) said: It is reported from a group of our rightly guided predecessors that there is an accepted Du'a after each completion of Qur'an; and the legally approved type of invocation is when the person supplicates for himself, parents, teachers and for other Muslim believers (Mu'minin) .Allah knows best.