Ask your politicians if they even read CETA
CETA (Comprehensive Economic and Trade Agreement) is not about free Trade, it is not comprehensive and it's not even an agreement.
Here are the Finnish MEPs (Member of the European Parliament) who voted for CETA last February:
Suomen Sosialidemokraattinen Puolue/Finlands Socialdemokratiska Parti
Suomen Sosialidemokraattinen Puolue/Finlands Socialdemokratiska Parti
Kansallinen Kokoomus 
WHAT IS CETA
This treaty will basically increase investors rights, meaning, big companies will have more power over our elected governments of Canada and all member States of the European Union.
The EU parliament just voted for it on February 2017, and if our national parliaments do not vote against it, we will be stuck with even more neoliberal policies in a time when so many of us already understood that capitalism has reached its limits, as so many studies and poles have been showing.
IT IS NOT COMPREHENSIVE:
It is 1598 page long, only recently publicly available and simply unreadable. Please download it here to see it for yourself. Its twice the size of Cervante's Don Quixote (see picture, yes twice that thick!). Do you think politicians have read it and understood it? Attac Germany had to hire a team of experts to decode it independent of the lobbyism. So, has your MEP did the homework?
IT IS NOT ABOUT FREE TRADE
Tariffs between most countries all over the world are already very low and mechanisms regulating these have been around for long with the World Trade Organization for example. How many of us have american phones, ate MacDonald's food, are wearing clothes from Bangladesh?... We are flooded with global products.
Having some tariffs is actually good. We can hold negotiating power between countries, to stimulate local products and guess what, it raises taxes, that thing which pays for our great schools and hospitals in Finland (where I live).
And if it is all about free trade, why not with all the world? A trade agreement excluding even as much as just one country is a protectionist measure against that one country.
All rich countries became so, due to protectionist measures. Doing so, heavily state subsidized products would be consumed internally and would smash the competition from abroad.
USA was a bastion of protectionism till the 1940s which made its cotton and steel industry reach top levels. But on more contemporary examples, the High Tech industry would have ever arisen under a free trade market, without the subsidies and protectionism of governments. Take computers, in the 1950s these were huge clunky things. The USA state financed them on 100% for several years. Dell and then IBM grew stronger from it and state financing was slowly reduced after years. What is true about computers is true about may others. For example, aeronautics, automation, GPS, bio-technology, pharmaceutical industry, even services such as tourism. These have all been heavily state subsidized until being strong enough to be fit for market. Free markets did not create computers. It did not create your smartphones, which only came to be, from state financed space research for example. Innovation needs a balance between protectionism and liberalism.
IT'S NOT AN AGREEMENT
CETA was negotiated in secrecy, such as the previous TTIP, NAFTA, the ongoing deal with India and EU, and others. There has been no public discussion nor consultation. It is an agreement between corporations and politicians who are lobbied by rich corporations.
Is this an agreement between the European and Canadian population?
Lobbyists are well dressed, rich and well educated people, going to politicians offering them free trips and lunches to convince them how good the ideas they are representing are. Is this democracy? Is this one person one vote, or is this one euro one vote system?
How can a democracy work with such discrepancies of influence? None of the MEPs above replied to the questions I sent them about CETA in 2016. They would have had if I would have bought them a 1st class flight to a dinner in Manhattan.
If it is an agreement between people and for people, and for free trade, why can't people move freely between these countries then? In 1994, at the same time NAFTA came to effect, Bill Clinton militarized the border between Mexico and USA. Why would you do so when you create a free trade agreement? It is clear that the economic miracle expected from NAFTA would benefit big business only, not the general population. And the results of NAFTA are out there, the life quality of the majority of population decreased dramatically, specially in Mexico. We can expect the same with CETA.
- Foreign corporations will be able to steer EU legislation in closed doors
- A company can demand a compensation from the implementation of legislation protecting health or the environment, to be paid by the taxpayers
- After a privatization, it is not possible to renationalize
- It prohibits us to create rules that would prevent banks from becoming too big to fail. 
- Most likely, and learning from previous treaties such as NAFTA, job conditions for the majority of the population will deteriorate, as unions will not be as effective 
- Environmental disasters are also expected as occurred in Mexico
- More CO2 emissions from mass transportation
- More Intellectual Property rights (IPRs), with great impact in the pharmaceutical industry with likely increase on the prices of medicines
- and much more
Take notice that if you read the report, which I did as much as I could stay awake by doing so, there is no executive summary and specially no evaluation of the risks involved in this agreement.
Be critical about it, why are such treaties negotiated in secrecy? Why would you negotiate anything in secret? Likely to take advantage over someone else's interests, in this case, the majority of the population. Agreements are fine, if you are going to win it. In this case, the negotiators win over the population's rights and the environment.
WHAT TO DO
The rhetoric of the politicians who are promoting the treaty is the same as of the 1993's debate between Al Gore and Ross about the polemic NAFTA. The discourse there was the same as today: all other previous free trade agreements were just bad designed, but now we got it, now we are better at it so we will do it right. 
You have the list of the Finnish MPs who voted for it. Contact them for clarification and ask them if they agree what is in there. I sent my questions to them before the voting in February and no one replied. Who will be accountable if we are stuck with an agreement which will undermine our rights and environment?
We must demand a public discussion about it, we demand a referendum.
The full speech by Pedro Aibéo on August 2017 in Helsinki, Finland, on the demonstration against CETA:
Pedro Aibéo 27.08.2017
 retrieved from https://stop-ttip.org/
 quoted from Monbiot's article "The transatlantic trade deal TTIP may be dead, but something even worse is coming"
 “union organizing is essentially impossible. Corporations can operate internationally, but unions can’t-so there’s no way for the work force to fight back against the internationalization of production. “ from https://chomsky.info/secrets03/
 The negative consequences of NAFTA are there now and Ross' warnings about the economy inequality of mexico and the USA, where any kind of free trade agreement would first need to level up the living standards of both economies and inject capital into the weaker ones to balance the markets was disregarded. EU adopted this principle with maybe better outcome.
Also a good accout on uions, related to the USA: https://hbr.org/2016/04/americas-uneasy-history-with-free-trade
About the author:
Pedro Aibéo is a trained Design Architect and Civil Engineer. He is at present a Kone Säätiö Research Fellow, a Visiting Associate Professor at UNAM University, Mexico and at Wuhan University of Technology, China, and a Lecturer and Doctoral Candidate at Aalto University, Finland on "Architectural Democracy". He is the founder and Artistic Director of “Cidadania” theatre+games group, a professional Musician at Homebound, the founder and Chairman of the World Music School Helsinki, a drawing teacher at the croquis nights and at Kiasma and a comic novelist.